Past Seminars

 Wed, OCT 10, 2018 
SPEAKER: Paolo Ventura (INAF - Osservatorio Astronomico di Roma)
TITLE: Dust from AGB stars
ABSTRACT: Stars evolving through the Asymptotic Giant Branch are generally regarded as important contributors to the overall dust production in the Universe. The latest generation of AGB models includes the description of the formation and growth of dust grains in the wind, thus allowing the determination of the dust yields from this class of objects. In this contribution we  will discuss how dust production is sensitive to the mass and the metallicity of the stars and present some applications of these results to the interpretation of infrared observations of the evolved stellar populations of galaxies.

contact: Gabriele Cescutti

Wed, OCT 3,  2018 
SPEAKER: George Ellis (University of Cape Town, Cape Town, ZA)
TITLE: On the philosophy of cosmology
ABSTRACT: After summarising the standard background models and perturbed models of cosmology, this talk will consider problems with these models; the crucial issue of the uniqueness of the universe, and consequent key importance of consistency tests; what we can say about the origin of the universe; limits to what we probably ever will know because of the visual horizon, particle horizon, and physics horizon; and make some brief comments on the issue of the multiverses and criteria for scientific theories• It will also comment on various top down (contextual) effects in cosmology and emphasize that the current state of the universe is not predictable from initial data at early times, because of quantum uncertainty 

contact: Stefano Borgani

 

Fri, SEP 28, 2018 @ 11:30AM --- extra seminar 
SPEAKER: Pragati Pardhan (The Pennsylvania State University (PSU), University Park, PA, USA)
TITLE: Exploring on-board transient detection with Athena Wide Field Imager


ABSTRACT: X-ray transients are among the most enigmatic objects in the cosmic sky. The unpredictability and underlying nature of their transient behaviour has prompted much study in recent years. While significant progress has been made in this direction, a more complete understanding of such events is often hampered by the delay in the rapid follow-up of any transient event. An efficient way to mitigate this constraint would be to devise a way for on-board detection of such transient phenomenon. The Athena/Wide Field Imager (WFI), with its 40’ × 40’ field of view can add some valuable contribution to this. In this work, we discuss an algorithm for the on-board detection of X-ray transients with WFI. We will also present a few test cases for the feasibility test of that algorithm on simulated Athena/WFI data. Finally, we discuss what type of X-ray transients are best suited for on-board detection from WFI, their probability of detections and the useful science that can follow.

contact:  Elena Rasia 

 

 

Wed, SEP 26, 2018 
SPEAKER: Sergio Ortolani (Physic and Astronomy Dept - Padova University, Padova, IT)
TITLE: The astronomical view of the climatic changes


ABSTRACT: The Earth climatic change is a debated subject but it is often influenced by simple preconceptions. Instead the Earth climate is a very complex system with many factors interacting. We will present an overview with the most recent results in the field and a specific analysis from an astronomical point of view, including new data and what we learned from other planets.

contact: Francesca Matteucci
 
 
 

Mar, SEP 11, 2018 @11:30AM -- EXTRA SEMINAR 
SPEAKER: Michele Trenti (AU)
TITLE: The SkyHopper Space Telescope: Big Science with a Tiny Telescope
ABSTRACT: Orbiting telescopes, large or small, have been so far confined to complex missions run by government agencies. However, thanks to dramatic technological improvements, CubeSats (nano-satellites based on standardised dimensions) are now offering new scientific opportunities. I will discuss how observations from space will advance astronomy in the next decade, and motivate within this context the SkyHopper mission concept, a proposed 12U CubeSat (~20kg mass) with an infrared space telescope, envisioned to be launched by 2022. SkyHopper will carry a four channel camera covering the spectral range from 0.8 to 1.7 micron simultaneously, and be capable of autonomously pointing to new targets within two minutes. The combination of timeliness on target and low-noise infrared image quality from space will offer a facility unique in the world for multiple areas of astronomy, from discovery of potentially habitable Earth-size planets around nearby cool stars to measurement of the Cosmic Infrared Background, which encodes information of galaxy formation processes across time. SkyHopper's rapid-response infrared imaging will also be ideal to complement current and future high-energy satellites such as Swift, SVOM, and the Hermes constellation to detect gamma-ray bursts generated by the explosion of massive stars out to the edge of the observable Universe.

contact: Fabrizio Fiore

Wed, SEP 5, 2018 
SPEAKER:  Mario Gennaro (STScI, Baltimore, MD, USA)
TITLE: The environmental dependence of the subsolar initial mass function
ABSTRACT: Understanding whether the Initial Mass Function (IMF) varies with environment will advance our detailed understanding of star formation and provide an empirical foundation for interpreting the observations of star-forming galaxies throughout cosmic history. In particular, very low-metallicity systems, like Local Group ultra-faint dwarfs, provide clues towards understanding the conditions in which stars formed in the early Universe, before the epoch of re-ionization. I will present recent results from both optical and near-infrared HST observations that probe the stellar populations of 6 nearby ultra-faint Milky Way dwarf satellites down to 0.4 (optical, using ACS) and 0.2 (near-IR, using WFC3) solar masses. Our analysis suggests that the IMF slope of such objects is flatter than that in the Milky Way. We observe a correlation between the IMF slope and the metallcitiy of the galaxies, with the most metal-poor ones having a more bottom-light IMF, i.e., fewer low-mass stars, relative to the Milky Way. Moreover, there is large variance in the IMF shape among the 6 galaxies observed in the optical. Obtaining measurements reaching well below the Milky Way IMF turnover mass of 0.5 Msun is very costly with HST, and feasible only for the closest UFDs. Near-future missions like JWST and WFIRST will help us probe an even smaller mass regime, reaching close to the hydrogen burning limit.

contact: Francesca Matteucci

 

Wed, JUL 11, 2018 
SPEAKER: Nilandri Paul (IUCAA: Inter-University Centre for Astronomy and Astrophysics, Pune, IN)
TITLE: Halo model of HI galaxies and their scaling relations
ABSTRACT: Modelling the distribution of neutral hydrogen (HI) inside dark matter halos is a key towards studying the evolutionary history of the galaxies in the cosmological context. A popular tool for modelling the connection between galaxies and dark-matter halos is the halo occupation distribution model (HOD). The speaker will talk about a novel approach, based on this HOD framework, to infer the HI-dark matter connection at the massive end of HI galaxies from radio HI emission surveys, using optical properties of low-redshift galaxies as an intermediary. This scaling model constrained using the two-point correlation function and the mass function data of HI galaxies from the ALFALFA survey produce relations consistent with the semi-analytical models of galaxy formation and direct observations from matched sample analysis. Some preliminary forecasts based on this model for future observations of HI and optical galaxies from SKA and EUCLID/LSST will also be discussed.

contact:  Pierluigi Monaco

 

Wed, JUN 27, 2018 
SPEAKER: Marcella Brusa (DIFA:Dipartimento di Fisica e astronomia, Università di Bologna, BO, IT)
TITLE: Observational evidences of Quasar feedback and its impact in galaxy evolution
ABSTRACT: It is well established that gas accretion onto SMBH  powers Active Galactic Nuclei over the entire range of their observed properties such as mass and luminosity, and over the entire cosmic history. Gas outflowing from the AGN power source is most likely responsible of the complex interplay between the nuclear engine and the host galaxy properties, which is commonly referred to as feedback. Winds propagating at much larger scales (Galactic outflows) can represent a crucial diagnostic of AGN feedback. Both numerical simulations and observations have shown that the nature of outflows in AGN is multiphase, and that each gas phase embeds a fundamental piece of information on the driving mechanism and on the effect on the host galaxy. In this talk I will review the progresses obtained in the past 2 years to shed light on the presence and effects of Quasar winds, and on the multi-phase nature of such phenomena.

contact: Gabriella de Lucia

Thu JUN 21, 2018 
SPEAKER: Iacopo Bartalucci (CEA-Saclay, Paris, FR)
TITLE: XMM-Newton and Chandra combined analysis of the most massive galaxy clusters at z~1
ABSTRACT:  Massive galaxy clusters represent an ideal laboratory to test our models in a mass regime where structure formation is driven mainly by gravity. Furthermore, the properties of high redshift clusters can be compared with local samples to investigate the evolution and assembly of large structures across cosmic times. Within this context, we present a detailed study of the spatially resolved thermodynamic and hydrostatic mass profiles of the five most massive clusters detected at z~1 via the Sunyaev-Zel'dovich effect, using a method which optimally exploits information from XMM-Newton and Chandra observations. The combination of Chandra’s excellent spatial resolution and XMM-Newton’s photon collecting power allows us to spatially resolve the profiles from the core to the outskirts, for the first time in such objects. Evolution properties are investigated by comparison with the REXCESS local galaxy cluster sample. Finally, we discuss the current limitations of this method in the context of joint analysis of future Chandra and XMM large programs and, more generally, of multi-wavelength efforts to study high redshift objects.

contact:  Barbara Sartoris

 

Wed, JUN 13, 2018 
SPEAKER: Fabrizio Fiore (INAF-OATS, Trieste, IT)
TITLE: The science of HERMES: a constellation of nano-satellites for high energy astrophysics and fundamental physics
ABSTRACT: A distributed instrument, such that consisting of nano-satellites carrying simple X-ray detectors, can provide accurate (arcmin to arcsec) and prompt (within minutes) localisation of high energy transients, such as gamma ray bursts and the electromagnetic counterparts of gravitational wave events. In addition, once the position of the transient is computed, the signals registered by the different detectors can be realigned in time and added together to improve the statistics. This can allow the investigation of the temporal structure of transients down to a fraction of microsecond, providing crucial information on one hand on the physics of the transient inner engine, and, on the other hand, on the granular structure of space-time, through the study of light-travel effects. The advantages of a distributed instrument based on nano-satellites are: a) modularity, which allows redundancies with the associated lower risks; b) the possibility to expand (and/or improve) the experiment with the time; c) low cost and quick development.

contact: Fabrizio Fiore

Wed, JUN 6, 2018 
SPEAKER: Fabrizio Tavecchio (INAF-OA Brera, Milano, IT)
TITLE: The Cherenkov Telescope Array: deepening our view at the extreme edge of the electromagnetic spectrum
ABSTRACT: In the next years we expect a dramatic leap in our knowledge of high-energy astrophysical phenomena, triggered by the first observatory for very-high-energy gamma-ray astronomy, the Cherenkov Telescope Array (CTA). Thanks to the unprecedented sensitivity (more than one order of magnitude better than current instruments), the improved angular resolution and the wide energy coverage (from 20 GeV up to 300 TeV), CTA carries an enormous scientific potential for discovery. After an introduction of the detection technique and the expected performances, I will review some of the more interesting physical topics in the focus of CTA. In particular I will discuss the possibility to discover the most extreme galactic accelerators (so-called Pevatron), to study extreme phenomena acting in relativistic jets and to characterize the extragalactic background light and the intergalactic magnetic field.

contact: Stefano Cristiani

Tue, JUN 5, 2018 @ 11:30 -- EXTRA SEMINAR 
SPEAKER: Matteo Maturi (Zentrum fur Astronomie / Institut fur Theoretische Astrophysik, Heidelberg University, Heidelberg, DE)
TITLE: EasyCritics: search for giant gravitational arcs in wide field surveys
ABSTRACT: The identification of arcs and multiple images produced by galaxy groups and galaxy clusters is a non trivial task. This is because of their low surface brightness, the instrumental noise, the PSF which tends to reduce their length-to-width ratio and the image blending which is likely to occur because they form in crowded fields. We circumvent all these issues by adoping a strategy in which their identification does not rely on the images but instead it takes advantage of the photometric galaxy catalogs. In brief: EasyCritics, uses the Light Trace Mass (LTM) criteria to build a gravitational lensing model in which each galaxy contributes to the total mass distribution according to its redshift (lensing depends on angular diameter distances), luminosity (the "larger the luminosity" the "larger the attributed mass") and spatial correlation with other galaxies (for dense areas, a smooth dark matter halo is add). In this way the code is able to blindly derive the expected lensing signal in field field survey and identify the structures which are likely to produce strong lesing features. Moreover it returns the geometrical properties and effective Einstein radious of the identified critical curves. Being based on photometric catalogs, the code is fully complementary to other arc finders based on images. In this talk I will present the method and discuss some of its applications to the CHFTLens data.

contact: Emiliano Munari

Fri, JUN 1, 2018 -- SEMINARIO STRAORDINARIO/EXTRA
SPEAKER: Danielle Wood (MIT, Cambridge, MA/USA)
TITLE: The Role of Space Technology to Support Sustainable Development
ABSTRACT: Professor Danielle Wood leads the new Space Enabled Research Group at the MIT Media Lab. The Space Enabled Research Group advances justice in Earth’s complex systems using designs enabled by space. Technology from space already advances justice by supporting the attainment of the Sustainable Development Goals. There are six space technologies that have been contributing to the Sustainable Development Goals for decades, but barriers remain that limit their impact. These technologies include satellite earth observation, communication, positioning, microgravity research, technology transfer and inspiration via research and education. The Space Enabled Research Group implements projects with development leaders at the multi-lateral, national, regional and local scale to apply space technology in support of their initiatives. During these projects, Space Enabled implements an integrated design process that includes techniques from engineering design, art, social science, complex systems modeling, satellite engineering and data science. During this talk, Prof Wood will discuss the role of space to spur innovation and development.

contact: Giovanni Vladilo

Wed, MAY 30, 2018 
SPEAKER: Mara Salvato (MPE, Garching, DE)
TITLE: AGN studies in the era of wide-angle and all-sky surveys 
ABSTRACT: Active Galactic Nuclei (AGN) are not longer considered part of a small and exotic source population but are now widely accepted to play a significant role in the evolution of galaxies through cosmic time. However, even fifteen years after the realization of the close link between the mass of the black hole and the properties of the hosting galaxy many details of the interconnection remain unresolved.  Two complementary approaches are followed to deepen our understanding; detailed studies of individual nearby AGN provide insight into the physics that trigger AGN activity and link it to the spatially resolved host properties, while the large samples of AGN collected from surveys access the population properties and their impact on the evolution of their hosts with redshift and environment. This second approach is hampered by technical challenges that can severely bias the results. In my talk I will focus on how these challenges (such as, e.g., multiwavelength counterparts identification and redshift determination) where solved in surveys of few square degrees (e.g., COSMOS, XMM-XXL, Stripe82X) and show how what we have learned so-far can prepare us to the new challenges that the next generation of wide-angle and all-sky sky surveys of galaxies and AGN (e.g., SRG/eROSITA, EUCLID, LSST, ASKAP/EMU) will pose.

contact: Elena Mason

Fri, MAY 25, 2018 @ 11:30 --- EXTRA SEMINAR 
SPEAKER: Jader Monari (INAF IRA, Villafontana - BO, IT)
TITLE: Installation of the SKA Aperture Array Verification 1
ABSTRACT: In this talk I will present AAVS1 (Aperture Array Verification 1), telling the vicissitudes of the INAF team during the first installation in Australia of the first prototype station with 256 antennas, in the missions held in March, August and November 2017. The installation was in the deep Australian outback in the Murchison region that is hosting the country for the Square Kilometer Array program, the low frequency radio telescope of the future, which will count at least 128,000 antennas distributed in 5000Kmq at the end of phase 1 of the program (2024). The presentation in Italian will be introduced by a general overview of the program with a surprise ending …

contact: Riccardo Smareglia

Wed, MAY 23, 2018 
SPEAKER: Veronica Strazzullo (LMU, Munich, DE)
TITLE: Environmental quenching in the most massive galaxy clusters at z~1.5
ABSTRACT: I will present first results from a galaxy population study in the five most distant clusters identified in the South Pole Telescope Sunyaev Zel’dovich survey (SPT-SZ), based on a dedicated 4-band HST and Spitzer follow-up of the complete z>1.4 tail of the SPT-SZ cluster sample (z~1.4-1.7). The wide survey volume of SPT-SZ, and the cluster selection to first order independent of cluster galaxies, make this sample ideally suited for studying galaxy populations in the rarest, most massive (>4x10^14 Msun) clusters at the cosmic epoch bridging the formation of massive cluster galaxies at z>~2 with their passive evolution regime at z<1. Based on photometric classification of quiescent and star-forming galaxies, we measure quiescent galaxy fractions at high stellar masses log(M/Msun)>10.85 of >~ 80% in the cluster core, yielding environmental quenching efficiencies in the range ~0.5-0.8 in the inner r<0.5xr500 cluster region. Our results thus suggest that, at least in the central regions of the most massive clusters, the suppression of star formation in massive galaxies with respect to their field analogs already effciently occurs earlier than z~1.5.

contact: Alex Saro

 Wed, MAY 16, 2018 
SPEAKER: Xiaoting Fu (INAF-OABO, Bologna, IT)
TITLE: Lithium: insights (problems) in astrophysics and its Galactic evolution
ABSTRACT: Lithium is widely used as a tester to the cosmological model, a probe of stellar structure, and an age indicator of young stellar clusters. It is the very element that presents deep insights yet many problems to astrophysics. I will briefly discuss problems and puzzles that Li introduces in astrophysics, including cosmological Li problem, Li-rich giants problem, Li problem in the Sun, and Interstellar Li content, then focus on the Galactic Li evolution. Using the Gaia-ESO survey data our group recently find a different Galactic Li enrichment history in the Galactic thin disc compared to the Galactic thick disc. A Li decline is also found for super-solar metallicity stars, if it is real, Li would be the first element we know whose absolute abundance declines with metallicity

contact: Elena Mason

Wed, MAY 9 , 2018
SPEAKER: Remco van der Burg (ESO, Garching, DE)
TITLE: The spatial distribution of high-mass to ultra-diffuse galaxies, in galaxy clusters and groups
ABSTRACT: Measurements of the radial distribution of galaxies in clusters show how galaxies trace the underlying dark matter distribution, and provide constraints on the physics related to their evolution in these environments. I will present measurements on the radial distribution of galaxies in two cluster samples, which span about 8 Gyrs of lookback time. By matching local galaxy clusters to their progenitors at high redshift, we study how clusters assemble their stellar mass content. Interestingly, this suggests that the central part of the stellar mass distribution of local galaxy clusters is already in place at redshift, and any further growth seems to happen in an inside-out fashion. I will also focus on the abundance and spatial distribution of ultra-diffuse galaxies (UDGs, which have the luminosities of dwarfs but sizes of giant galaxies) in clusters and groups. These mysterious galaxies have been found to be surprisingly abundant in local clusters, but their origin remains puzzling. I will summarise recent results on their abundance as a function of host halo mass, and the first direct measurement of their masses using weak gravitational lensing. I will discuss implications and future prospects to learn more about the properties and formation histories of these elusive galaxies.

contact: Alex Saro

TUE, MAY 8 , 2018 @ 11:30 --- EXTRA SEMINAR
SPEAKER:  Steve B. Howell (NASA/Ames Research Center, Moffett Field, CA, USA)
TITLE: Revealing the Fundamental Properties of Exoplanets and their Host Stars with High-resolution Imaging
ABSTRACT:  Our team has built and delivered new high-resolution imaging instruments to the NOAO WIYN and Gemini North telescopes.  These new visible light, dual-channel speckle interferometric instruments provide the highest resolution imaging available on any single telescope, even those in space. This talk will focus on our long term exoplanet characterization program in which we study the host star environment and its effect on exoplanet properties. I will discuss measurements of the distribution in brightness and separation of exoplanet host star systems as well as characterization of the radii and densities of small, rocky exoplanets. We find that 50% of exoplanet host stars are binaries, similar to that in field stars, with the majority of bound companions orbiting with stellar separations of less than 0.2”, typically <10 AUs. I will present our observational program and the information it provides on stellar parameters, exoplanet validation, true exoplanet size distributions and occurrence rates, and planet formation scenarios.

contact: Elena Mason

Wed, MAY 2, 2018 
SPEAKER: Priyanka Singh (INAF-OATS, TS,  IT) 
TITLE: X-ray and SZ constraints on the properties of hot gas in galaxies
ABSTRACT: The hot (T>10^6 K), diffuse gaseous medium in galaxies, also referred to as Circumgalactic medium (CGM), is a huge reservoir of galactic baryons. It is also poised to be a potential reservoir of galactic missing baryons. The hot CGM manifests itself in thermal SZ effect as well as X-ray emission. However, it is difficult to detect these signals from individual galaxies due to the low gas density. There have been recent detections of the stacked thermal SZ and X-ray emission from massive galaxies (M_vir ~ 10^12-10^13 M_sun). We use these measurements to constrain the amount and distribution of the hot CGM. We find that a simple power law distribution of the gas (ne prop r^-1.2) can explain these measurements well. Our model predicts that hot CGM contains approximately 20-30% of the baryon budget in massive galaxies. Our predictions of the mass contained in hot CGM are comparable to the previous estimates of mass contained in other cooler phases of the CGM.

contact: Alex Saro

Wed, APR 18, 2018 
SPEAKER: Silvia Piranomonte (INAF-OARoma, Roma, IT)
TITLE: GW170817 optical/NIR follow-up observations: the first evidence of kilonovae existence
ABSTRACT: On August 17th 2017 the first electromagnetic counterpart of a gravitational wave (GW) event originated by the coalescence of a double neutron star system (GW 170817, Abbott et al. 2017) was finally observed. A world-wide extensive observing campaign was carried out to follow-up and study this source. In this talk I will describe our unique spectroscopic dataset acquired with the VLT which allowed to characterize and identify the optical counterpart of GW 170817 as the first compelling example of a "kilonova", a transient source powered by radioactive decay of heavy elements resulting from the r-process nucleosynthesis of ejected neutron star matter. All the activities I will describe are expected to provide means and opportunities to all the European astronomical communities to have a leading role in the GW astronomy and Time Domain Astronomy.

contact: Francesca Matteucci

Wed, APR 11, 2018 
SPEAKER: Steffen Hagstotz (Ludwig-Maximilians-Universität & Universitätssternwarte, Munich, DE)
TITLE: Hunting Neutrinos and Modified Gravity with Clusters of Galaxies 
ABSTRACT: Considerable effort in cosmology is focused on understanding the statistical nature of the cosmological density field that underlies the observable large scale structure. Clusters of galaxies trace the largest, non-Gaussian peaks of the matter density, and their abundance is a sensitive probe of both underlying cosmological parameters as well as physics governing structure formation. In my talk I will explain how cluster abundance can be used to search for modifications of gravity via its impact on spherical collapse and why neutrinos are a crucial component in these searches. In addition astrophysical signatures within the cluster can be a key signal themselves and I will demonstrate how to incorporate them in searches to constrain deviations from general relativity.

contact: Barbara Sartoris

Wed, APR 4, 2018 
SPEAKER:  Mario Lattanzi (INAF-OATO, Torino, IT) 
TITLE:  Gravitational astronomy: the Gaia view. Status and prospects after 3.75 yr of science operation
ABSTRACT: The concept of precisely gauging a gravity-dominated Universe like ours through the individual observations of its fundamental constituents, the stars, immediately calls astrometry, the oldest quantitative specialty of astronomy, into play. For, the accurate measurement of the motions of stars in our Galaxy can provide access to cosmological signatures in its disk and halo, while astrometric experiments from within our Solar System can uniquely probe possible deviations from General Relativity. This talk will address the fact that, with the Gaia mission, astrometry has reached such levels to become a key player in the fields of local cosmology and experimental gravitation, or “Gravitational Astronomy”, as we like to call the combination of the two topics. It will be shown how accurate distances and absolute kinematics at the scale of the Milky Way, a revolution for stellar astrophysics, can, for the first time in situ, account for the predictions of the CDM model for the Galactic halo; and how, eventually, can map out the distribution of dark matter, or other formation mechanisms, required to explain the signatures recently identified in the old component of the thick disk. Selected results from the first data release (DR1) and updates on the status of the program at less than a month from DR2 (the Gaia second data release to the community worldwide will occur on April 25) are presented to the extent possible with the help of results from the astrometric pipelines operating at the Italian data processing center (DPCT). Final notes will dwell on to what extent the Gaia satellite can fulfill the expectations of gravitational astronomy and on what must instead be left to future, specifically designed, experiments.

contact: Andrea Zacchei

Wed, MAR 28, 2018 
SPEAKER: Paulo Lopes (Observatório do Valongo, Universidade Federal do Rio de Janeiro, Rio de Janeiro, BR)
TITLE: Optical Substructure and brightest cluster galaxy offsets of Sunyaev-Zel'dovich and X-ray Selected Galaxy Clusters
ABSTRACT: We used optical imaging and spectroscopic data to derive substructure estimates for local Universe ($z < 0.11$) galaxy clusters from two different samples. The first was selected through the Sunyaev-Zel'dovich (SZ) effect by the Planck satellite and the second is an X-ray selected sample. In agreement to X-ray substructure estimates we found the SZ systems to have a larger fraction of substructure than the X-ray clusters. We have also found evidence that the higher mass regime of the SZ clusters, compared to the X-ray sample, explains the larger fraction of disturbed objects in the Planck data. We have also verified a good agreement ($\sim 60 \%$) between the optical and X-ray substructure estimates. However, the best level of agreement is given by the substructure classification given by measures based on the brightest cluster galaxy (BCG), either the BCG$-$X-ray offset, or the magnitude gap between the first and second BCGs. We advocate the use of those two metrics as the most reliable and cheap way to assess clusters dynamical states. However, the BCG$-$X-ray offset threshold should be smaller than typically adopted in the literature. We recommend an offset of $\sim$0.01$\times$R$_{500}$. Regarding the magnitude gap the separation can be done at $\Delta m_{12} = 1.0$. 

contact: Andrea Biviano

Wed, MAR 14, 2018
SPEAKER: Andrea Merloni (MPE, Garching, DE)
TITLE: Understanding AGN evolution with large X-ray surveys: current constraints and prospects for eROSITA
ABSTRACT: The emergence of the three-dimensional structure of the cosmic web over the history of the Universe displays very distinctive features when observed in X-rays, where both the most massive collapsed structure (clusters of galaxies) and the most energetic events in the life of galaxies (AGN and Quasars) reveal themselves unambiguously. In the past 50 years, astronomers have used X-ray surveys to tackle fundamental questions for structure formation such as: How did supermassive black holes form and grow in the nuclei of galaxies? Why are their physical properties today so tightly linked to those of their hosts? What was the impact on the surrounding structures of the copious energy release, either in radiative or mechanical form, associated to the growth of such black holes in active galactic nuclei (AGN)? I will show how state of the art observations with Chandra and XMM-Newton have been used to give at least partial answers to some of these questions. I will also highlight the major limitation of existing X-ray surveys: many crucial aspects of the study of the connection between AGN and host galaxies cannot be explored because of the limited volume of the Universe explored. The next generation of wide-area, sensitive X-ray surveys designed to map the hot and energetic Universe will be heralded by eROSITA (extended ROentgen Survey with an Imaging Telescope Array), the core instrument on the Russian-German Spektrum-Roentgen-Gamma (SRG) mission, scheduled for launch in 2018. eROSITA will perform a deep survey of the entire X-ray sky, and will be about 30 times more sensitive than ROSAT in the soft energy band (0.5-2 keV), while in the hard band (2-8 keV) it will provide the first ever true imaging survey of the full sky. eROSITA is expected to yield a sample of around 3 million active galactic nuclei, which is bound to revolutionize our view of the evolution of supermassive black holes and their impact on the process of structure formation in the Universe

contact: Pierluigi Monaco

Wed, MAR 7, 2018 
SPEAKER: Roberto Decarli (INAF-OABO, Bologna, IT)
TITLE: Quasars at cosmic dawn: new light at the end of the dark ages
ABSTRACT: Quasars at z>6 (when the universe is <1 Gyr old) are arguably the most active objects in the early universe. The high luminosity of a quasar is powered by rapid accretion of gas (>10 Msun/yr) on a central black hole with mass >1E8 Msun. Their host galaxies are forming stars at humongous rates (100-1000 Msun/yr). Copious reservoirs of gas sustain both star formation and nuclear accretion. The very presence of such compact concentrations of matter suggests that high-z quasars reside in the extreme peaks of the cosmic density distribution, so quasars could be used to pin-point the first galactic overdensities. These extreme properties make quasars unique laboratories of the birth and early formation of black holes and massive galaxies. I will present our on-going efforts aimed at discovering and characterizing new z>6 quasars, and at studying their host galaxies and their environment.

contact: Valentina D'Odorico
 

Wed, FEB 28, 2018 
SPEAKER:  Francesco Ferraro (Physics and Astronomy Dept, Bologna University, Bologna, IT)
TITLE: An empirical clock to measure the dynamical age of star clusters
ABSTRACT: The observational properties of a special class of stars (the so-called Blue Straggler stars – BSS) in Globular Clusters are discussed in the framework of using this stellar population as probe of the dynamical processes occurring in these high-density stellar systems. In particular, the shape of the BSS radial distribution and their level of central segregation have been found to be powerful tracers of the level of the dynamical evolution of the hosting cluster, thus allowing the definition of an empirical “dynamical clock”.  

contact: Elena Mason

 

Wed, FEB 21, 2018 
SPEAKER: Annalisa Pillepich (MPIA, Heidelberg, DE)
TITLE: IllustrisTNG: the new frontier to understand the co-evolution of dark matter, gas and galaxies with cosmological simulations of structure formation
ABSTRACT: I will describe the numerical efforts to simulate galaxies with the moving-mesh code AREPO across an unprecedented range of halo masses, environments, evolutionary stages and cosmic times. In particular, I will focus on the IllustrisTNG project (www.tng-project.org), a collaboration among Heidelberg, Munich, New York and Boston. There we are simulating a series of three gravity+magnetohydrodynamics cosmological volumes (50, 100, 300 Mpc a side, respectively) capable of both resolving the inner structures of galaxies as small as the classical dwarfs of the Milky Way, as well as of sampling the large scale structure of the Universe with thousands among groups and clusters of galaxies. I will briefly explain what is explicitly and empirically solved in gravity+magnetohydrodynamics simulations for galaxy formation in a cosmological context and what is required and what it means to “successfully” reproduce populations of galaxies which resemble the real ones. I will therefore show novel insights allowed by the new simulations, ranging from the assembly of the most massive structures in the Universe, the coevolution of galaxies and their black holes, and our theoretical expectations for the distribution and properties of dark matter, gas and stars on large scales and within galaxies.

contact: Fabio Fontanot
Wed, FEB 14 , 2018
SPEAKER: Gianfranco Brunetti (IRA-INAF Bologna, BO, IT)
TITLE: LOFAR : opening a new observational window at low radio frequencies
ABSTRACT: The Low Frequency ARray (LOFAR) is the world’s largest effort to explore the radio sky at long wavelengths and is leading the rapid evolution of modern low-frequency radio astronomy on the path to the low frequency SKA. LOFAR is an new generation aperture synthesis array distributed on continental scale in Europe across the Netherlands, Germany, UK, France, Sweden, Poland, Ireland, and Latvia. Due to the unprecedented high processing and bandwidth requirements, innovative approaches for data transfer, handling and analysis are being driven making this radio telescope a unique laboratory to understand the modeling of ionospheric effects and calibration of long-baseline data at low frequencies. After an introduction to the LOFAR radio telescope and to the most important challenges for data transfer, calibration and imaging, I will focus on the most relevant LOFAR Key Science Projects. In particular I will make use of the recent achievements on galaxy clusters and radio galaxies to demonstrate the potential of LOFAR observations in producing a breaktrough in many areas of astrophysics and astrophysical plasmas in the next years. In the final part of the talk I will describe the ongoing actions carried out by INAF to join LOFAR and its upgrade to LOFAR 2.0. I will briefly discuss the status of the negotiations, the Italian roadmap and the opportunities for our community.

contact: Stefano Borgani

 

Wed, JAN 31, 2018 
SPEAKER: Davide Fiacconi (Institute of Astronomy, University of Cambridge, Cambridge, UK)
TITLE: Formation, growth, and coalescence of supermassive black holes
ABSTRACT: Supermassive black holes are fundamental constituents of galaxies. Yet, many outstanding questions remain: how do supermassive black holes form? How do they initially grow? What is the fate of black hole binaries in different environments? In this talk, I will review the status of affairs behind this questions and I will highlighting some particular aspects, such as (i) the role of supermassive stars and quasi-stars in the direct collapse scenario, (ii) the state of the interstellar medium and the implications for mass transport in typical high-z galaxies as inferred from state of the art cosmological simulations, (iii) our attempts to improve accretion models for hydrodynamical large-scale simulations, and (iv) the evolution of massive black hole pairs in gas-rich and stellar-dominated environments.

contact: Stefano Borgani

NO SEMINAR on the WEEK starting on JAN 22, 2018

Wed, JAN 10, 2018 
SPEAKER: Anja von der Linden (Stony Brook University, Stony Brook, NY/USA)
TITLE: Cosmology with Galaxy Clusters: from Weighing the Giants to LSST
ABSTRACT: Surveys of galaxy clusters provide a sensitive probe of cosmology by measuring the evolution of the halo mass function. However, already current cluster surveys are systematically limited by uncertainties in the relation between cluster mass and observables (e.g. X-ray luminosity, cluster richness, SZ decrement). Cluster weak lensing is the most promising observational method to calibrate the mass scaling to the needed precision, but requires the control of systematic errors to a few percent each.  I will discuss the "Weighing the Giants” (WtG) project, which carefully investigated and quantified all sources of systematic uncertainty, resulting in accurate weak lensing masses for 51 clusters.  From a sample of ~200 clusters selected from the ROSAT All-Sky Survey, WtG places some of the tightest constraints on a number of cosmological parameters, including the dark energy equation of state, neutrino masses, and modified gravity.  Furthermore, when adopting the WtG mass calibration, the results from Planck CMB temperature anisotropies and Planck cluster counts are consistent without invoking the need for new physics.  These results bode extremely well for future cluster surveys which will be able to utilize LSST's weak lensing capabilities to anchor the cluster mass scale.

contact: Andrea Biviano
 
VENERDI, DEC 15, 2017 -- SEMINARIO STRAORDINARIO IN ITALIANO, DIVULGATIVO -- ORE 11:00
SPEAKER: Stefano Borgani (INAF-OATS, Trieste, IT)
TITLE: Il lato oscuro dell'Universo
ABSTRACT: Questo seminario divulgativo ha lo scopo di illustrare come si e’ giunti a formulare quello che viene considerato il modello cosmologico standard, in cui il contenuto dell’Universo e’ dominato da due componenti, materia oscura ed energia oscura, la cui natura e’ ad oggi sostanzialmente sconosciuta. Allo scopo di svelare il mistero di tali componenti oscure dell’Universo, la comunita’ astronomica internazionale ha deciso di sviluppare una serie di progetti per la costruzione di telescopi sia basati a terra che nello spazio, nei quali INAF ed il nostro Osservatorio sono coinvolti. 

contact: Stefano Borgani

Wed, DEC 6, 2017 -- 3rd yr. PHD STUDENTs SEMINARs 
SPEAKER: 3rd yr PhD students Uni TS: Matteo Pinamonti
TITLE:  Detection and Orbital Architecture Characterization of Planetary Systems Around Cool Stars
ABSTRACT: It is pivotal to intensify the efforts towards the detection and characterization of extrasolar planets around M dwarfs, since new discoveries will help bring the statistical support still needed for the study of peculiar classes of planets. The many open issues on M dwarfs host and their planetary systems, and the development of new methodologies to investigate them, are the foundation of the motivation for my PhD work. I report my work on performance analysis of three periodogram tools, the Generalised Lomb-Scargle Periodogram, its modified version based on Bayesian statistics, and the multi-frequency periodogram scheme called Frequency Decomposer. The results illustrated reinforce the need for the strengthening and further developing of the most aggressive and effective ab initio strategies for the robust identification of low-amplitude planetary signals in RV data sets. I describe the high-performance algorithms for single and multiple Keplerian signals modeling used by the research group I am part of, and their applications both on blindly analyzed simulated RV measurements and on high-precision HARPS archive data. I then report the first results I obtained from the analysis of RV data collected as part of the HADES (HArps-n red Dwarf Exoplanet Survey) project, that is the detection of a long-period low-mass planet orbiting the M1 dwarf GJ15A, which was already known to host a short-period Super Earth. Since the host star is part of a binary system with the M dwarf GJ15B, I studied a suite of numerical simulations of the long-term perturbations of the planetary system. Finally, I outline the strategy and preliminary results of the ongoing Bayesian analysis of the occurrence rates of planets around small mass stars and the global detectability of the HADES survey.
SPEAKER: 3rd yr PhD students Uni TS: Anna Zoldan 
TITLE: On the role of cold gas in galaxy evolution
ABSTRACT: Galaxy evolution results from a complex interplay of physical processes, that act on a wide range of scales and times. One crucial piece of this complex puzzle is cold gas. Indeed, all physical processes occurring within galaxies, as well as those related to interactions with the external environment, directly influence (or are regulated by) the dynamics and the content of cold gas. In this seminar, I will provide a brief overview of my PhD Thesis. I have taken advantage of state-of-the-art semi-analytical models of galaxy formation and evolution, and used them to explore the role of cold gas in the physical processes driving galaxy evolution. This approach allows a controlled analysis of individual galaxy histories, and of the contributions of the specific processes involved. I can, in this way, follow the origin of the observed relations, providing a physical interpretation for existing data and predictions for higher redshift.

contact: Gabriella de Lucia

Wed, NOV 29, 2017 
SPEAKER: Peter Mitchell ( CRAL, Centre de Recherche Astrophysique de Lyon, Lyon, FR)
TITLE:  The physics driving the star formation rates of star-forming galaxiesABSTRACT: It has been recognised for 10 years that the observed evolution of galaxy star formation rates at a given stellar mass does not agree with predictions from models and simulations. I will examine the various physical processes which play a role in these predictions, and argue that current observations imply that the efficiency of feedback must evolve with cosmic time. I will demonstrate different options for how this can be achieved empirically, and conclude by examining the behaviour of the Eagle simulations to see if there is a scenario which is preferred by current hydrodynamical simulations.

 contact: Gabriella de Lucia

Wed, NOV 22, 2017 -- 3rd yr PHD STUDENTs SEMINARs 
SPEAKER: Manuel Colavincenzo (Uni-TS, Trieste, IT)
TITLE:  Covariance matrix estimation for the statistics of galaxy clustering
ABSTRACT: The accurate determination of the cosmological parameters has become one of the key activities in modern cosmology: the understanding of the nature of the dark components of the Universe, dark matter and dark energy, as well as the study of the behavior of gravity at very large scales, is fundamental to improve our knowledge on the history and evolution of the Universe. The structures we observe today result from the growth of initial perturbations due to gravitational instability. The spectrum of these perturbations, and -therefore the statistical properties of the galaxy distribution, is defined by the cosmological model. Choosing between different models requires accurate theoretical predictions of the observables and precise modeling of their uncertainties. The modeling of the two-point statistics  is fundamental in order to describe the clustering strength of different structures on different scales. The analysis of the clustering statistics, two- and three-point functions, is fundamental but in order to perform any statistical analysis of the large-scale galaxy distribution, it is of primary importance to quantify the errors on these quantities. We study the problem of covariance matrix estimation for clustering. We first study the power spectrum and the bispectrum, quantities that encode a great part of the clustering information. Then we focus on the computation of the uncertainties on these quantities. To proper quantify the errors we have to include different effects that introduce different complications in the modeling.

contact: Gabriella de Lucia

Wed, NOV 15, 2017 
SPEAKER: Emiliano Sefusatti (INAF-OATS, Trieste, IT) 
TITLE: Neutrino Masses, N-body Simulations and Cosmological Perturbation Theory
ABSTRACT: A non-vanishing neutrino mass leads to a few percent suppression of matter perturbations, with respect to a massless neutrino cosmology, on all scales below their free-streaming scale. The effect allows to place constraints of the sum of neutrino masses from measurements of the galaxy power spectrum but it also constitutes a theoretical uncertainty in dark energy studies. For both these reasons its accurate description is particularly relevant. I will review how well numerical simulations and analytical methods can account for neutrino masses and argue that the interplay between the two approaches is particularly significant and fruitful for this specific problem. 

contact: E. Sefusatti 

Wed, OCT 25, 2017 
SPEAKER: Fabio Fontanot (INAF-OATS, Trieste, IT)
TITLE: Variations of the stellar initial mass function in semi-analytical models
ABSTRACT: I will discuss the implications of implementing a two independent variable Initial Mass Function (IMF) scenarios in semi-analytic models. These approaches provides a description of the dependence of the stellar IMF shape on the physical properties of model galaxies (either the SFR or the SFR surface density). In the framework of the GAEA (GAlaxy Evolution and Assembly) model, which features a detailed treatment of chemical enrichment and stellar feedback, I will show that realizations with a universal IMF predict a rather flat alpha/Fe-stellar mass relation. The models assuming a variable IMF, instead, are able to reproduce the observed increase of alpha-enhancement with stellar mass. This is mainly due to the fact that massive galaxies are characterized by larger star formation rates at high-redshift, leading to stronger alpha-enhancement with respect to low-mass galaxies. At the same time, the final stellar masses and mass-to-light-ratio of our model galaxies are larger than those estimated from the synthetic photometry assuming a universal IMF, providing a self-consistent interpretation of recent claims for IMF variations in massive galaxies, based on dynamical analysis of local early type galaxies. Indeed, the different variable IMF scenarios does not affect significantly the trend for shorter star formation timescales for more massive galaxies, but they can change significantly their star formation histories. Nonetheless, the definition of observational tests able to discriminate between these scenarios is challenging even for the next generation facilities.

contact: Fabio Fontanot

Mon, OCT 23, 2017 - EXTRA SEMINAR @ 15:30 
SPEAKER: Daniel Gruen (KIPAC/Stanford University, Stanford, CA, USA)
TITLE: Weak Lensing in the Dark Energy Survey
ABSTRACT: The Dark Energy Survey has combined analyses of galaxy clustering and weak gravitational lensing two-point correlation functions in its first year (Y1) of observations. The goal of this is to constrain cosmological parameters from lensing measurements of structure in the evolved Universe. The combination of two-point correlation functions provides information on the amplitude of density fluctuations (S8=0.794+0.029-0.027) and the dark energy equation of state (w=-0.80+0.20-0.22) that is competitive with Planck CMB data. When joint with probes of cosmic geometry, it yields the best measurement of these parameters to date. Besides reviewing these results and the technical advances that facilitated them, I will also give an outlook on upcoming work that provides a DES lensing view of higher than second moments of the matter density field.

contact: Mario Nonino & Alex Saro

Wed, OCT 18, 2017 
SPEAKER: Salvatore Orlando (INAF-OAPA, Palermo, IT)
TITLE: Connecting supernova explosions to their remnants through multi-dimensional magnetohydrodynamic modeling
ABSTRACT: Supernova remnants (SNRs) are diffuse extended sources often characterized by a rather complex morphology and a highly non-uniform distribution of ejecta. General consensus is that such a morphology reflects, on one hand, pristine structures and features of the progenitor supernova (SN) explosion and, on the other hand, the early interaction of the SN blast wave with the inhomogeneous circumstellar medium (CSM) formed in the latest stages of the progenitor evolution. Deciphering the observations of SNRs, therefore, might open the possibility to investigate the physical properties of both the interacting ejecta and the shocked CSM. This requires accurate and detailed numerical models which describe the evolution from the on-set of the SN to the full remnant development and which connect the emission properties of the remnants to their progenitor SNe. Here we show how multi-dimensional SN-SNR magnetohydrodynamic models have been very effective in deciphering observations of SNR Cassiopeia A and SN 1987A.

contact: Pierluigi Monaco

Wed, OCT 11, 2017 
SPEAKER: Alex Saro (INAF-OATS, Trieste, IT)
TITLE: The South Pole Telescope (SPT) cluster survey and its cosmological implications
ABSTRACT: The 10-meter South Pole Telescope (SPT) is a millimeter wavelength telescope designed to conduct sensitive measurements of the cosmic microwave background (CMB) at arc-minute resolution. The SPT has successfully conducted a 2500 square degree survey to find clusters of galaxies from their distortion of the CMB, known as the Sunyaev-Zel'dovich (SZ) effect. The surface brightness of the SZ effect is redshift independent which allows a SZ survey to provide a nearly mass limited cluster sample out to the earliest epochs of cluster formation. The SPT has identified ~700 of cluster candidates. Of these,~500 have been optically confirmed, with the majority being newly discovered clusters at z > 0.5. I will summarize the main results from the SPT cluster survey, including cosmological constraints from their measurement of the growth of structure.

contact: Stefano Borgani  

Wed, SEP 27, 2017
SPEAKER: Carlo Abate (Bonn University, Bonn, DE) 
TITLE: Carbon-Enhanced Metal-Poor stars: potpourri of stellar evolution, nucleosynthesis and binary stars.
ABSTRACT: Carbon-enhanced metal-poor (CEMP) stars are old, low-mass and low-metallicity halo stars that exhibit abundances of carbon relative to iron more than ten times higher than in the Sun, [C/Fe]>1. To understand the origin of CEMP stars it is necessary to investigate stellar evolution and AGB nucleosynthesis, mass transfer in binary systems, and the properties of the metal-poor stellar population in the Milky Way, for example the ages of the observed stars, the initial chemical composition with which they were born, the initial mass function, the fraction of binary stars and the distributions of separations at which binary stars were formed. In my talk I will show some examples of what can be learned from the study of CEMP stars.

contact: Gabriele Cescutti

Wed, SEP 20, 2017
SPEAKER: Giuseppe Murante (INAF-OATS, Trieste, IT)
TITLE: An experiment in Astrobiology: Exploring the climate parameter space of rocky planets
ABSTRACT: Astrobiology is a relatively new and fast-growing science, whose main characteristic is to need expertises from different science fields. I'll show how the climate of a planet influences its habitability. Astronomers from OATs, climatologists from CNR and experts in databases from OATs joined their efforts to build a fast, simplified, yet effective climate model and database for extra-solar planets. I will describe the model, its main feature, its validation, its application to a specific exo-planet (Kepler 452b). I will then show how such a model can be used to explore a huge parameter space and build a database that can be used to characterize classes of habitable planets. I will point out how this particular case is an good example of High-Throughput Computing (HTC). Our database can also be used, e.g., as a tool to get a first estimate of the habitability of a newly discovered rocky planet. Then I will describe possible future developements of such a research line, including the study of the effect of the biosphere itself on the habitability.

contact: Giuseppe Murante

Wed, SEP 6 , 2017 
SPEAKER: Julian Merten (Physics Dept., Oxford Uinv, Oxford UK & INAF-OABO, Bologna, IT)
TITLE: Lensing clusters: past, present and future
ABSTRACT:  The union of galaxy clusters and gravitational lensing turned out to be most prolific and a particularly versatile tool for astrophysics and cosmology. I will present a selection of our recent results based on data from the Cluster Lensing and Supernovae Survey with Hubble (CLASH), the Hubble Space Telescope Frontier Fields (HSTFF) and the Kilo Degree Survey (KiDS). The focus will be on dark matter density profiles derived from multi-wavelength probes, the concentration-mass relation of galaxy clusters, the calibration of the Planck cluster mass scale, lensed supernovae and the high-redshift Universe using clusters as cosmic telescopes. Towards the end of the presentation I will suggest possibilities to optimally exploit future surveys such as Euclid, LSST and WFIRST, where the focus will be on optimal mass mapping techniques and agnostic ways to characterise the full morphology of structure in the sky with computer vision and machine learning.  

contact: Andrea Biviano

Wed, JUN 28, 2017
SPEAKER:  Christopher Haines (INAF-OA Brera, MI, IT)
TITLE: VIPERS: Following the evolution of the star-forming galaxy population to z~1 with 100,000 spectra.
ABSTRACT: I present results from the recently completed VIPERS redshift survey which has obtained spectra for ~100,000 galaxies at redshifts 0.5-1.2 over 24 square degrees. By combining VIPERS and SDSS datasets, we explore the relationships between star-formation history, stellar mass and galaxy structure and how these relationships have evolved from z~1 to the present day, focusing in particular on the high mass limit of the blue cloud, beyond which galaxies cannot continue growing through star formation. I show how this high-mass limit has evolved significantly over the last 8 billion years, retreating steadily to lower stellar masses towards the present day, but also depends strongly on galaxy size, revealing a fundamental link between galaxy structure and "mass quenching".

contact: Andrea Biviano

Wed, JUN 21 , 2017
SPEAKER: Alessandro Sozzetti (INAF-OATO, Torino, IT)
TITLE: Exoplanet science with HARPS-N at TNG: The first luster
ABSTRACT: I will present results (old, but also new!) from the GTO and GAPS five-years long radial-velocity programmes with HARPS-N at TNG, describing the impact that high-resolution, high-precision spectroscopic data with this state-of-the-art facility have had in various research areas of the fascinating field of extrasolar planetary systems. I will then outline avenues for the future, continued exploitation of high-resolution spectroscopy at the TNG, particularly when seen as a leadership boon for the italian community in the exoplanet field.

contact: Matteo Pinamonti
 
 
Tue, JUN 20 , 2017 @ 12:00 -- EXTRA SEMINAR
SPEAKER: Isha Pahwa (Inter-University Centre for Astronomy and Astrophysics, Pune, IN)
TITLE: Analytical halo model of galactic conformity
ABSTRACT: Galactic conformity is an observation that satellite galaxies in groups whose central galaxy is red are preferentially red, even when the groups are restricted to reside in dark matter halos of the same mass. In this talk, I will present a fully analytical halo model of colour-dependent clustering which incorporates the effects of galactic conformity in a halo occupation distribution (HOD) framework. This model describes conformity through a correlation between the colour of a galaxy and the concentration of its parent halo, leading to a correlation between central and satellite galaxy colours at fixed halo mass. The strength of the correlation is set by a tunable ‘group quenching efficiency'. I will show that our model can separately describe the group-level correlations between galaxy colour (1-halo conformity) and large scale correlations induced by assembly bias (2- halo conformity). Further, I will talk about our analytical clustering results and compare them with that of mock galaxy catalogs, showing that this model is accurate at the 10-20 percent level for a wide range of luminosities and length scales.
contact: Emiliano Sefusatti
Wed, JUN 14, 2017
SPEAKER: Lara Nava (INAF-OATS & INAF-OABrera, Trieste, IT)
TITLE: Radiative processes and jet composition in Gamma-Ray Bursts
ABSTRACT: The nature of the radiative processes responsible for prompt and afterglow emission in Gamma-Ray Bursts (GRB) is far from being understood. The lack of a clear understanding on how radiation is produced is strictly related to other fundamental open questions in GRB physics, such as the jet composition (magnetic or baryonic), the location of the emitting region, and the nature of mechanisms regulating energy dissipation and particle acceleration. In this talk, I present some recent developments in the field. In the context of afterglow emission, I discuss the origin of high-energy (GeV) radiation detected in around 100 GRBs by the Fermi-LAT and the prospects for GRB detection with the CTA. In the context of prompt radiation, I present new, unexpected features recently discovered in prompt spectra, and I discuss how these new findings can help us to discriminate between different energy dissipation mechanisms and ultimately constrain the composition of GRB jets.
 
contact: Lara Nava 

Wed, JUN 7, 2017
SPEAKER: Andrea Grazian (INAF-OARoma, Roma, IT))
TITLE:  The space density and ionizing budget of high-z AGN: looking for the sources of Reionization
ABSTRACT: The Reionization of the intergalactic medium marks a turning point in the history of structure formation in the Universe. At present, the identification of the source population which ends up the Dark Ages and illuminates the Cosmic Dawn is still an open issue. Recent results from bright QSOs (M1450<-27) at z>4 observed by the Sloan survey indicate that they emit copious amount of ionizing photons, but their space density is still too low in order to reionize the Universe. Star-forming galaxies are more numerous but their escape fraction of ionizing photons is below few percent, still insufficient to keep the Universe ionized. Faint AGN could give an important contribution to the HI ionizing background and to the cosmic Reionization, depending on their abundance at low luminosities (L<0.1L*) and at high redshift (z>4). Recent results on the faint end of the AGN luminosity function at z>4 have been derived thanks to deep NIR observations with HST and faint X-ray detections in the 7Msec Chandra images in the CANDELS/GOODS-South field and in shallower CANDELS fields (GOODS-North and EGS). A dedicated spectroscopic survey with VLT and LBT starts to show that the ionizing escape fraction of faint AGN at z>4 is significant, and thus they can provide a fundamental contribution to the Reionization of the Universe.

contact: Valentina D'Odorico

Wed, 31 May, 2017
SPEAKER: Filippo Fraternali (Universita' di Bologna, BO, IT)
TITLE:  How gas ends up in galaxies
ABSTRACT: The evolution of star-forming galaxies is a history of continuous accretion of fresh gas from the surrounding environment. The main evidence of this accretion is indirect coming from the estimate of depletion times and the chemical composition of gas and stars in our Galaxy. In recent years, observational evidence has been accumulating that star-forming galaxies are surrounded by massive gaseous halos containing a large amount of multiphase gas. To understand how this gas falls and accretes to feed star formation we must understand the complex physics of the interphase between the discs and the halo. After a review of the current observations, I present theoretical work and hydrodynamical simulations supporting the idea that gas accretion comes from the condensation of the galactic hot halo triggered by supernova feedback. I discuss some key predictions of this model and its consequences for the evolution of star-forming galaxies.

contact: Gabriella de Lucia

Wed, MAY 24, 2017
SPEAKER:  Rob Yates (MPE, Garching, Munich, DE)
TITLE:  From tiny dwarfs to giant clusters: Modelling the chemical evolution of galaxies across cosmic time using semi-analytic models
ABSTRACT: In this talk, I will present recent results from L-GALAXIES, a semi-analytic model of galaxy evolution. Such models allow us to efficiently study a full and diverse range of galaxies in the Universe, from tiny 'dwarfs' to the largest 'galaxy clusters', as they evolve. I will focus on the chemical evolution of galaxies, describing how stars explode and pollute their surroundings with heavy elements over cosmic time. I will compare results from L-GALAXIES to the latest observations of the iron abundance in the hot gas around galaxy clusters, the oxygen abundance in the cold gas within nearby dwarfs, and the alpha enhancements in the stellar populations of old early-type galaxies. I will conclude by unveiling the latest version of L-GALAXIES, which will allow us to study a whole new range of galaxy phenomena on even smaller, sub-galactic scales in the very near future. 

contact: Gabriella de Lucia

 

Wed, MAY 17 , 2017
SPEAKER: Silvio Bonometto (INAF-OATS, Trieste, IT)
TITLE: SCDEW: cosmologies with strong DM-DE coupling and a WDM component.
ABSTRACT: In the era of big projects to inspect the DE nature, new cosmological models are welcome when predicting effects such experiments can test. Accordingly, cosmologies with strong DM--DE coupling and WDM, predicting a null result in planned Big Physics programs, apparently diverge from the mean stream of thought. Being based on the finding of a kinetic attractor solution in the radiative era, they however meet quite a few existing datasets, otherwise hard to reconcile with LCDM models, even with extreme stretching of baryonic physics. Among them, let me list MW and M31 satellites, dwarf galaxy profiles, concentration distribution, Lyman-alpha excess; not to forget the severe conundrums infecting LCDM models and the natural option, within SCDEW, that the same scalar field is Dark Energy and plays a key role in inflation.

contact: Stefano Borgani, Giuseppe Murante
 

Wed, MAY 10, 2017
SPEAKER: Anna Wolter (INAF-OA Brera, Milano, IT)
TITLE: ESON e dintorni
ABSTRACT: L'ESO, l'Osservatorio Europeo Australe, ha da poco compiuto 50 anni ed è il più produttivo osservatorio astronomico da Terra. Oltre a costruire i più grandi telescopi al mondo, l'ESO considera tra i suoi compiti fondamentali anche quello di divulgare le scoperte e di stimolare la fantasia del pubblico e l'interesse nei confronti dell'astronomia.  Allo scopo di raggiungere più facilmente sia il grande pubblico che i "tecnici" della divulgazione è stato istituita dall'ESO un Rete di Divulgazione Scientifica, o ESON (ESO Science Outreach Network). Come rappresentante di ESON per l'Italia mi adopererò per mostrarvi come funziona questa "rete". Cercherò anche di lanciare qualche piccolo aggancio per stimolare l'interazione reciproca.  

contact: Massimo Ramella

Thu, MAY 4, 2017 @ 14:15 -- SEMINARIO EXTRA
SPEAKER: Danilo Marchesini (Tufts University, Phys. & Astro. Dept., Medford, MA, USA)
TITLE: The Growth of Today's Most Massive Galaxies over the last 12.8 Gyr of Cosmic History
ABSTRACT:  I will present recent findings on the evolution of the properties of the progenitors of local ultra-massive galaxies over the past 11.2 billion years (i.e., since redshift z=3), along with recent results on their environment out to z=2 and of the relative role played by merging and in-situ star formation in the growth of their stellar mass content in the last 10 billion years. I will present the most recent and comprehensive census of quiescent, unobscured and dusty star-forming galaxies as a function of stellar mass since z=3. I will then show very exciting results from a spectroscopic follow-up programs of candidates of very massive galaxies at 1.5<z<4, along with the latest constraints on the abundance of very massive galaxies in the early universe, as the frontier is pushed into the first 1.5 Gyr of cosmic history (i.e., z>4). I will conclude by giving a preview of latest on-going observational efforts (e.g., HFF-DeepSpace, NMBS-II, and others).

 
contact: Gabriella de Lucia
Wed, MAY 3,  2017
SPEAKER:  Claudio Grillo (Dark Cosmology Center, Copenhagen, DK & Uni MI, Mi, IT)
TITLE: Probing the cores of galaxy clusters with strong gravitational lensing
ABSTRACT: Superb Hubble Space Telescope imaging and extensive Very Large Telescope spectroscopy, along with fundamental developments in the strong lensing modelling phase, have allowed us to measure with unprecedented precision the inner mass distribution of massive galaxy clusters acting as gravitational lenses. I will show how strong lensing models have been employed to (1) reproduce the observed multiple-image positions of distant galaxies substantially better than thought possible even just a few years ago, (2) predict accurately position, magnification and time delay of a lensed supernova (SN ‘Refsdal’) before it became visible, (3) probe the structure and substructure properties in the cores of galaxy clusters, and (4) estimate the values of the cosmological parameters defining the geometry of the Universe. I will conclude by outlining the roadmap towards possible extensions beyond the current frontiers of strong lensing studies in galaxy clusters and their implications for cosmology.
contact: Emiliano Munari

Wed, APR 26 , 2017
SPEAKER : Fabrizio Fiore (INAF-OAR, Roma, IT)
TITLE: AGN wind scaling relations
ABSTRACT: Why black holes  in galactic nuclei have masses proportional to bulge masses and luminosities? Why did galaxies at a certain point of their cosmological evolution, stop to form stars? What is the path(s) and the mechanism(s) leading the transition from gas rich, star-forming galaxies, to red passive galaxies, deprived of all their gas? Theory and few observations suggest that AGN driven super winds (=feedback) play a major role in all these transformations. The two main building blocks of this scenario are: 1) AGN winds, which inject energy in their environment; 2) the interaction of these flows with the galaxy interstellar matter, and its physical/chemical/geometrical modification. I will first review AGN winds seen in different gas phases and at different scales and derive AGN wind scaling relations.  I will then plug these studies in the broader framework of AGN evolution and discuss the perspectives of extending these studies up to z=1-3, the golden epoch of AGN and galaxy activity.

contact: Stefano Borgani

 

Wed, APR 12, 2017
SPEAKER: Eleonora Ferroni ed Elisa Nichelli (INAF Ufficio comunicazione)
TITLE: Dalle stelle alle stampe: come funziona la comunicazione INAF
ABSTRACT: Da maggio 2016 l’Inaf ha formalizzato una nuova struttura dedicata alla comunicazione. Com’è organizzata? Chi ci lavora? Cosa si intende per press release, news, conferenza stampa, embargo, comunicato congiunto, virgolettato e cose simili? A chi serve? E, soprattutto, perché parlano di qualunque cosa tranne che delle mie ricerche? Nel corso di questo incontro, dedicato a tutti ma in particolare a ricercatrici e ricercatori (precari e non, dai laureandi agli associati già in pensione) tenteremo di soddisfare queste e altre curiosità e dubbi su due dei quattro compiti della struttura di comunicazione: Ufficio stampa e Media INAF. E di raccogliere i vostri suggerimenti. L’obiettivo è migliorare la comunicazione interna, riducendo al minimo i fraintendimenti e cercando di rendere il più possibile serene – magari perfino divertenti – le occasioni d’interazione con noi.

contact: Massimo Ramella

 Wed, APR 5, 2017
SPEAKER: Santi Cassisi (INAF-OA Teramo, TE, IT)
TITLE: The Multiple Population Phenomenon in Galactic Globular Clusters
ABSTRACT: In the last decade accurate photometric and spectroscopical observations have provided sound evidence that Galactic Globular Clusters can not be longer considered the prototype of Simple Stellar Populations. In this talk we present the most recent updates concerning the empirical evidence and discuss the theoretical framework required for interpreting observations. Current shortcomings in the interpretation of how the multiple stellar populations formed in a given cluster are also discussed.

contact: Fabio Paisan

Wed, MAR 29, 2017
SPEAKER: Alessandro Bressan (SISSA, Trieste, IT)
TITLE: From Stars to Black Holes
ABSTRACT: The recent spectacular direct discovery of gravitational waves with the Advanced LIGO detectors showed that stellar black holes (BH) exist in nature and that, when they are orbiting around each other in a binary system, they may merge in less than the Hubble time.  The masses of the components  measured in the first BH merger event detected were surprisingly large, more than 25 solar masses, and unexpectedly quite discrepant from  the predictions of most theoretical  models.  Clarifying the reasons of this discrepancy is one of the fundamental steps to understand the formation channels and the rates of BH binary mergers. I will review the recent advances in the theory of massive stars with particular focus on those aspects that rendered possible the prediction of the existence of such heavy stellar BHs.

contact: Stefano Cristiani

Wed, MAR 22, 2017
SPEAKER: Luciano Rezzolla (Institute of Theoretical Physics, Frankfurt Univ., Frankfurt, DE)
TITLE: The physics and astrophysics of merging neutron-star binaries
ABSTRACT: I will argue that if black holes represent one the most fascinating implications of Einstein's theory of gravity, neutron stars in binary system are arguably its richest laboratory, where gravity blends with astrophysics and particle physics. I will discuss the rapid recent progress made in modelling these systems and show how the inspiral and merger of a binary system of neutron stars is more than a strong source of gravitational waves. Indeed, while the gravitational signal can provide tight constraints on the equation of state for matter at nuclear densities, the formation of a black-hole--torus system can explain much of the phenomenology of short gamma-ray bursts, while the the ejection of matter during the merger can shed light on the chemical enrichment of the universe.

contact: Pierluigi Monaco

Tue, MAR 21 , 2017 -- EXTRA SEMINAR
SPEAKER: Jianhua He (Durham University, Durham, UK)
TITLE: Testing gravity with small scale redshift space galaxy clustering
ABSTRACT: Understand the nature of the gravity is one of the most important motivations of future large galaxy surveys such as Euclid and DESI. Although the accuracy of the measurements of galaxy clustering has been improved dramatically during the past decade, approaching percent level, there are still some challenges to make a final conclusion of theory of gravity and tell the fate of the Universe. This is largely due to the potential systematics in observations and uncertainties in theories.  In this talk, I will talk about major challenges and systematics in testing gravity on cosmological scales and also discuss possible ways to get around them. My talk has three parts. In the first part, I will talk about the challengeson the theory side. In the second part, I will talk about systematics in real data and how to mitigate them. In the last part, I will compare theory with data and show that predictions in LCDM match data very well. Therefore, the possibilities of modified theories of gravity are diminished.       

contact: Emiliano Sefusatti

Wed, MAR 15 , 2017
SPEAKER: Nicolas Martinet (Argelander Institut fur Astronomie, Bonn Univ, Bonn, DE)
TITLE: Cosmological constraints from shear peaks with KiDS and Euclid
ABSTRACT: The peak statistic in weak lensing reconstructed mass maps is a new powerful tool to probe cosmology. Peaks trace the Universe large scale structures, but on the contrary to the two-point correlation function of the shear (aka cosmic shear), they are also sensitive to the non-linear regime of the growth of structures. In that sense they are similar to galaxy clusters. Although high peaks correspond to clusters, there is additional information contained in the low peaks arising from large scale structure projection effects.In this talk, I will introduce weak lensing peaks and compare them to cosmic shear and cluster abundance. I will apply shear peaks to the Kilo Degree Survey (KiDS), and discuss their cosmological constraints in light of the recent tension found between KiDS cosmic shear and Planck CMB. Finally, I will forecast the peaks cosmological constraints attainable with the Euclid survey, and compare them with the constraints expected from galaxy cluster counts. 

contact: Andrea Biviano

Wed, MAR 8, 2017
SPEAKER: Giuseppe Lodato (Universita' di Milano, Milano, IT)
TITLE:  Planet formation in the ALMA era
ABSTRACT: High resolution imaging of protostellar discs through ALMA at sub-mm wavelengths and through extreme adaptive optics systems, such as SPHERE, in the near infrared, is revolutionizing our view of the earliest phases of planet formation. Young protostellar discs reveal a wealth of substructures in the form of spiral arms, gaps and rings, horseshoe features and warped structures. On the one hand, such structures are the signposts of planet formation, being likely shaped by the gravitational interaction of the disc with newly born planets. On the other hand, their presence strongly affects the dynamics of dust grains in the disc, which are the main ingredient for the formation of rocky and gaseous planets. In this talk, I will discuss the new perspectives opened by such discoveries in the theoretical description of the dynamics of gas and dust in a young, planet forming disc. I will show our recent hydrodynamical simulations of the coupled gas and dust dynamics in protostellar discs, obtained with the SPH code PHANTOM, in order to describe the features observed in high resolution imaging and in order to identify new dynamical processes that are likely at work in these systems.

contact: Pierlugi Monaco

Wed, MAR 1, 2017
SPEAKER:  Giorgio Calderone (INAF-OATS, Trieste, IT)
TITLE:  QSFit: Automatic analysis of optical AGN spectra
ABSTRACT: The software is very easy to use and provides estimates of: AGN continuum luminosities and slopes at several restframe wavelengths; luminosities, widths and velocity offsets of 20 emission lines; luminosities of iron blended lines at optical and UV wavelengths; and host galaxy luminosities.  QSFit fits all the components simultaneously using an AGN continuum model which extends over the entire available spectral range, in order to probe the broad-band AGN continuum and avoiding influences of localized features in the spectrum.  The QSFit code is released as free software, and the whole fitting process is customizable for specific needs. I will also present a new catalog of spectral properties of 71,251 SDSS spectra of AGN with z < 2, analyzed with QSFit.  Such catalog allowed us (for the first time) to estimate the AGN continuum slope on a very large sample, and to show that there is no evident correlation between the continuum slopes and the redshift.

contact: Stefano Cristiani

Wed, FEB 15, 2017
SPEAKER:  Sergio Molinari (INAF-IAPS, Roma, IT)
TITLE:  VIALACTEA: the Milky Way as a Star Formation Engine
ABSTRACT:  The Milky Way Galaxy, our home, is a complex ecosystem where a cyclical transformation process brings diffuse baryonic matter into dense unstable condensations to form stars, that produce radiant energy for billions of years before releasing chemically enriched material back into the ISM in their final stages of evolution. Star formation is the trigger of this process, eventually driving the evolution of ordinary matter in the Universe from its primordial composition to the present-day chemical diversity necessary for the birth of life. The VIALACTEA project incorporates in a consistent and inter-operable framework all major last-generation Galactic Plane surveys from the mid-infrared to the radio, in continuum and spectroscopy, to deliver a transformational view of our Milky Way Galaxy. From diffuse ISM clouds, through a pervasive network of filamentary structures, down to the formation of dense clumps, the VIALACTEA surveys trace the morphology and physics of dust structures at all spatial scales from the individual star formation site to the panoramic view of entire spiral arms. VIALACTEA deploys a homogeneous analysis and classification scheme for nearly 30,000 candidate filamentary structures and more than 100,000 dense clumps with heliocentric distance determinations. We are now able to complete the first resolved map of the Star Formation Rate in the Milky Way and analyse in detail its variation with Galactocentric distance and with respect to spiral arms, as well as in comparison to star formation triggering agents. The suite of Galactic Plane surveys images, data cubes and catalogues in VIALACTEA constitutes a Knowledge-Base augmented with metadata information that allows seamless data discovery over very inhomogeneous datasets. A new Visual Analytics application will be demonstrated to access, visualise in 3D and analyse the VIALACTEA Knowledge-base.

contact: Marco Molinaro

Wed, FEB 8, 2017
SPEAKER: Melanie Johnston Hollitt (Victoria, University of Wellington, Wellington, NZ)
TITLE:  Science with the Murchison Widefield Array – the Low frequency precursor to the SKA
ABSTRACT: The Murchison Widefield Array (MWA) is the first fully operational precursor to the Square Kilometre Array (SKA). Since Phase I of the MWA was completed in late 2012, the instrument has collected over 10 TB of data spanning the frequency range of 72 – 300 MHz. This has resulted in over 80 publications and 1500 citations for a diverse range of science covering radio galaxies, pulsars, galactic magnetism, the ionosphere, exoplanets, EoR, supernova remnants, HII regions, relics and halos in galaxy clusters. Highlights of this work include the completion of a sky survey south of +30 degrees, detection of plasma ducts in the ionosphere, discovery of large numbers of new supernova remnants and a very large number of new diffuse sources (relics and halos) in clusters. I will discuss the MWA as an instrument and present the science highlights of the first 4 years of operations, in particular focusing on the work associated with galaxy clusters. If time permits I will briefly describe the current upgrade process for the telescope. 

contact: Elena Rasia

Wed, FEB 1, 2017
SPEAKER:  Andrea Pastorello (INAF-OAPD, Padova, IT)
TITLE:  The dying breath of massive stars
ABSTRACT: With the label of Intermediate Luminosity Optical Transients (ILOTS)", I refer to several types of eruptive variables with luminosities intermediate between classical novae (M > -10) and core-collapse supernovae (M < -15). Some ILOTS are believed to be stellar mergers, or unusual sub-luminous supernovae. Others are known to be major outbursts of massive stars (including different classes of super/hypergiants, luminous blue variables and early-type Wolf-Rayet stars), that can mimic the observed parameters of true supernovae, although the star survives the eruptive event. They are usually labelled as "supernova impostors". More interestingly, occasionally, major outbursts are observed a very short time (weeks to a few years) before terminal supernova explosions. I will review some interesting ILOTS, a new powerful tool to link the progenitor stars with the different scenarios of supernova explosions.

contact: Elena Mason

Wed, JAN 25, 2017
SPEAKER:  Matteo Viel (INAF-OATS, Trieste, IT)
TITLE:  Investigating the Intergalactic Medium at Trieste Astronomical Observatory
ABSTRACT: I will review my decade of research activity on the Intergalactic medium at Trieste Observatory by summarizing successes and failures.
contact: Matteo Viel, Stefano Borgani

Wed, DEC 14, 2016
SPEAKER:  Antonello Provenzale (Institute of Geosciences and Earth Resources,CNR, PI, IT)
TITLE: Earth's climate dynamics
ABSTRACT: The Earth's climate is a complex system that includes many interacting components coupled to each other through positive and negative feedback loops. But the most striking characteristics of the Earth is the presence of life, which modulates and even determines the dynamics of the planetary climate: climatic change induces important modifications in the Earth's ecosystems, and biospheric processes significantly affect the climate of our planet. In this seminar, I shall discuss some of the many links between climate and biosphere, considering the full hierarchy of modeling approaches. Biospheric models are often based on empirical assumptions, and attempt at reducing the overwhelming complexity of the couplings between biological and climatic processes. The talk starts by discussing the possibility of multiple equilibria as a consequence of climate-vegetation feedbacks, then address the concept of ecosystem engineers and habitat construction, to finally reach planetary scales and consider how climate "on the large" can be determined by the action of living organisms. The issue of cross-scale interactions will be explored and the many existing uncertainties will be considered.

contact: Giovanni Vladilo & Laura Silva

Wed, DEC 7, 2016 
SPEAKER: Gianluca Israel (INAF-OARoma, Monte Porzio Catone, IT)
TITLE:  Mining the beat of the X-ray sky
ABSTRACT: The detection and characterization of X-ray periodic signals has played and still play a role of paramount importance in the process of identifying new compact objects or new classes of pulsators, and studying the mechanisms powering the observed emission. Since the number of high quality time series stored in the present-day X-ray archives has increased by a factor of more than 100, these data clearly hold a huge potential for new discoveries and make data mining an urgent task to achieve them. Thanks to the new-generation high energy missions, which have wider energy ranges and higher sensitivities, the number of detected X-ray sources has increased by a factor of more than 10. In the last years we have applied the state of art of timing techniques to carry out a systematic search for new X-ray pulsators in the archival database of Chandra and XMM-Newton (more than 1.000.000 light curves) identifying tens of new X-ray  pulsators (and still counting). In this talk I will briefly present the ChAndra Timing Survey at Brera And Roma astronomical observatories (CATS@BAR), and the Exploring the X-ray Transient and variable Sky (EXTraS) projects, focusing on the general properties of the new sample of pulsators and on the EXTraS products which will be delivered to the community during 2017. I will then focus on the few but extremely important extragalactic X-ray pulsars identified so far by the EXTraS project: the first X-ray pulsar discovered in the Andromeda Galaxy associated to a rare low mass X-ray binary, and two new members of the emerging class of pulsating ultraluminous X-ray sources, the luminosity of which cannot be accounted for by the standard accretion models, even assuming beamed emission.

contact: Elena Mason

Wed, NOV 30, 2016 
SPEAKER:  Marco Fulle (INAF-OATS, Trieste, IT)
TITLE:   Rosetta and the pebbles forming planetesimals
ABSTRACT: Latest news on what Rosetta is finding on how Solar Systems form and evolve.

contact: Marco Fulle & John Danziger

Wed, NOV 23 , 2016 
SPEAKER: Claudio Dalla Vecchia (IAC, ES)
TITLE: The EAGLE project: modelling galaxy formation and evolution
ABSTRACT: I will talk about the improvements in hydrodynamical cosmological simulations and the modelling of the formation and evolution of the observed galaxy population within the EAGLE simulation project. I will show results from EAGLE and other projects using the EAGLE model. I will also describe what data has been made publicly available, and give a couple of examples on how it could be used.

contact: Pierluigi Monaco

Wed, NOV 16, 2016 
SPEAKER: Zhi-Yu Zhang, (IfA, University of Edinburgh, UK & ESO, Garching, DE)
TITLE:  A fundamental constraint on the imaging of molecular gas and dust in the early Universe
ABSTRACT: Images of dust continuum and CO line emission are powerful tools for deducing structural characteristics of galaxies such as disk sizes, H2 gas velocity fields, and enclosed H2 and dynamical masses. We report on a fundamental constraint set by the Cosmic Microwave Background (CMB) on the observed structural and dynamical characteristics of galaxies as deduced from dust continuum and CO line imaging at high redshifts. As the CMB temperature rises in the distant Universe, the ensuing thermal equilibrium between the CMB and the cold dust and H2 gas progressively erases all spatial and spectral contrasts between their brightness distributions and the CMB. This strongly biases the recoverable H2 gas and dust mass distributions, scale lengths, gas velocity fields, and the dynamical mass estimates, for high redshift galaxies. This limitation is unique to mm/submm wavelengths, and unlike its known effect on the global dust continuum and molecular line emission of galaxies, it cannot be simply addressed. We nevertheless identify a unique signature of CMB affected continuum and line brightness distributions, namely a rising rather than diminishing contrast between such brightness distributions and the CMB once frequencies beyond the Raleigh-Jeans limit are used for imaging the cold molecular gas and dust in distant galaxies.  Such effects progressively change the apparent gas and dust distribution and velocity field, leading to biased size and mass estimates of high-redshift galaxies, which will be obtained with ALMA, JVLA, and SKA.

contact: Pierluigi Monaco

 

Wed, NOV 9, 2016 
SPEAKER:  Simone Scaringi (MPE, Garching, DE)
TITLE: One (disk) ring to rule them all: linking accretion from protostars to supermassive black holes
ABSTRACT: From planets to super-massive black holes, accretion is the process by which most objects in the Universe grow in mass. Accretion requires angular momentum to be lost from the in-falling material, usually resulting in the formation of a so-called accretion disk. Although the importance of accretion disks have been recognised for many years, the detailed physics and dynamics are still poorly understood. Over the last decade we have been able to link the accretion physics of stellar-mass black holes with those of super-massive black holes, with over nine orders of magnitude difference in mass. However, we do not yet know if the physics of accretion can be extended to include other systems, such as accreting white dwarfs, neutron stars, and young-stellar objects. Despite being seemingly different observationally, I will show how all these different types of accreting systems have revealed strikingly similar properties. Being just the "tip of the iceberg", the discoveries I will present suggest that a single unifying physical model exists to explain how accretion disks behave throughout the Universe, irrespective of the mass, size, or type of the accreting object.

contact: Elena Mason

Wed, OCT 26, 2016
SPEAKER:  Giuseppe Longo (Universita' di Trieste, Trieste, IT)
TITLE:  La nascita della filosofia digitale
ABSTRACT:  Dopo decenni di filosofie nichiliste, deboli o decostruzioniste, quando ormai i filosofi sembravano aver rinunciato definitivamente allo sguardo globale sul Tutto, accontentandosi di veder chiaro in qualche settore d’indagine limitato (filosofia del linguaggio, filosofia della mente…), compare una filosofia dalle sembianze antiche, con una sua ontologia e con un’idea forte del divenire: la filosofia digitale. Se le sembianze sono antiche, i contenuti di questa filosofia sono decisamente nuovi, poiché appartengono a ll’area delle tecnologie dell'informazione. Infatti l’impulso decisivo al costituirsi del nuovo quadro della realtà è stato fornito dal computer, il quale sotto questo profilo si presenta come una vera e propria “macchina filosofica”, capace di suggerire con forza che tutte le grandezze della natura sono finite e discrete, e possono quindi essere rappresentate esattamente mediante quantità intere, escludendo dunque ogni variabile infinita, infinitesima, continua o localmente indeterminata e soggetta alla casualità. Inoltre queste grandezze fisiche corrispondono a nient'altro che a configurazioni di bit e la loro evoluzione temporale è governata da processi computazionali. Per la filosofia digitale l’Universo è un grande computer che calcola senza posa e con estrema naturalezza e precisione il proprio stato successivo

contact: Stefano Borgani

NO SEMINAR ON OCT 19, 2016 --- ADASS meeting  

Fri, OCT 14 , 2016 @ 11:30 -- EXTRA SEMINAR
SPEAKER: Alvaro Rojas-Arriagada (Observatoire de la Cote d'Azur, Nice, FR) 
TITLE:  The galactic bulge as seen by Gaia-ESO survey
ABSTRACT: The Milky Way bulge is a cornerstone for our understanding of galaxy formation. As a massive and old stellar component, the Galactic bulge keeps in its stellar content a fossil record of the early chemodynamical process which shaped the structures currently sitting at the central kiloparsecs. By studying the chemical composition of long-lived low mass stars it is possible to disentangle the eventual mix of stellar populations assembling the Galactic bulge, and so understanding the different mechanisms responsible for their formation and chemodynamical evolution. In this talk I will present several results obtained from the analysis of Gaia-ESO survey data. The Gaia-ESO survey is an ongoing large spectroscopic survey with the aim of observing 10^5 stars sampling different Galactic populations, from star forming regions to the old stellar halo. In particular, I will present results concerning chemical content for a sample of ~2500 bulge red clump stars, relating it with kinematics and spatial distribution. The presence of two main stellar bulge populations, as reveled from this analysis, is discussed in the context of current models of bulge formation.

contact: Francesca Matteucci

Wed, OCT 12, 2016 
SPEAKER:  Lucia Pozzetti (INAF-OABO, Bologna, IT)
TITLE:  The quenching history of galaxies: a test for the models of their formation
ABSTRACT: For the development of a realistic model of the formation and evolution of galaxies is necessary a systematic comparison with observations.  This aspect is crucial since a discrepancy is indicative of a lack from the point of view of physical processes and of the values assigned to the free parameters in the construction of the model.  In this work we analyze some of the semi-analytical models of galaxy formation (Merson et al. 2013, Henriquez et al. 2013, 2014, De Lucia & Blaizot 2007, Monaco et al. 2006, Guo et al. 2013), making use of the redshift evolution of the stellar mass function of galaxies (MF) as statistical tool indicative of the quenching history of galaxies.  They were compared (using mocks to test sample selection effects) to MFs at 0<z<3 derived from observations (SDSS, BOSS, zCOSMOS, VIPERS, VVDS, COSMOS, etc), to probe the effects of various modeling of physical processes.  In addition, models are compared separately for star-forming galaxies and passive galaxies, by adopting different criteria (based on the specific star formation rate and/or on the specific color), also to assess the effects of that choice. Finally we evaluated the evolution with cosmic time of the number densities, in particular of quiescent galaxies in various ranges of mass, and the redshift at which their number densities are halved to explore the differences between models and observations about the timing of their quenching and assembly history according to their mass.

contact: Pierluigi Monaco

Wed, OCT 5, 2016
SPEAKER: Vincenzo Antonuccio-Delogu (INAF-OACT, Catania, IT)
TITLE:  AGN backflows: a mechanism to self-regulate AGN activity.
ABSTRACT: When a relativistic AGN jet enters the Interstellar Medium of its host galaxy, an internal backflow from the hotspot develops. We demonstrate from first principles (Crocco theorem) that this is a necessary consequence of mechanical jet emission. The flow lines bring very low angular momentum gas towards the central accreting region, and could ultimately feed the central Supermassive Black Hole (SMBH). We have studied in detail the circulation of gas inside the cocoon performing an exhaustive set of numerical simulations, and developed a hydrodynamic model of this flow. We show that this circulation arises because of the presence of entropy and density gradients in two critical points: near the hot spot and the meridional plane of the cocoon. We find simple solutions for the streamlines within the bow shock, solving the appropriate fluid dynamic equations, and we use these solutions and the simulations to predict the mass inflow rates towards the central regions. We find that this  backflow affects the accretion disc by compressing it and thus modifying the efficiency of magnetic field lines diffusion, which is directly connected to the jet's mechanical power. The time scales of these backflows are only weakly dependent on the jet/ISM parameters. The modulation of jets power results into a self-regulatory mechanism of AGN activity, that is not directly controlled by, but possibly controls,  the star formation rate within the central circumnuclear disk, and ultimately its feedback on star formation quenching

contact: Gabriella de Lucia

Wed, SEP 28 , 2016
SPEAKER: Matteo Bianconi (Institute for Astro- and Particle Physics, Innsbruck Univ., Innsbruck, AT)
TITLE:  Star formation and black hole accretion activity in rich local clusters of galaxies
ABSTRACT: Cluster of galaxies are ideal to study the effect of environment on galaxy evolution. We studied the clusters Abell 983 and 1731, targeted with a multiwavelength campaign of observations that include deep infrared Spitzer and near-IR Palomar imaging, and optical WIYN spectroscopy. The observations cover the vast range of possible environments, from the very dense cluster centre to the very rarefied cluster outskirts and accretion regions. The analysis of the specific star formation rate reveals evidences of galaxy pre-processing on a filament-like structure, extending from Abell 1731. Additionally, we found a decrease in number of star forming galaxies and AGN towards the cores of both clusters. A further comparison with the data from the Illustris simulation appears to confirm that dense environments are accelerating the ageing process of galaxies and blocking further accretion of cold gas that fuels both star formation and black hole accretion activity.

contact: Andrea Biviano

Wed, SEP 21, 2016
SPEAKER: Massimiliano de Pasquale (Mullard Space Science Laboratory, UCL, Dorking, UK)
TITLE:  The 80 Ms X-ray light-curve of the exceptional GRB 130427A.
ABSTRACT:  GRB 130427A was the brightest gamma-ray burst detected in the last 30 years. With an isotropic energy release of 8.5×10^53 erg and redshift of 0.34, it combined very high energetics with a relative proximity to Earth in an unprecedented fashion. Sensitive facilities such as XMM-Newton and Chandra have detected the X-ray afterglow of this event for a record-breaking baseline longer than 80 million seconds. The light curve  displays a simple power-law over more than three decades in time. In my talk, I examine the consequences of this result for a few models proposed to interpret GRB 130427A and, more in general, the implications of this outcome in the context of the standard forward shock model.

contact: Stefano Cristiani

Wed, SEP 7, 2016
SPEAKER: Lucio Crivellari (IAC & Universidad de la Laguna, Tenerife, ES; INAF-OATS)
TITLE:  Foundational aspects of spectral line formation theory
ABSTRACT: The observed finite width of spectral lines is due to both internal and external causes. The latter must be ascribed to the motion of the absorbing/emitting atoms (Doppler broadening) and the random perturbations brought about by neighbouring atoms. The former is a natural consequence of the intrinsic atomic structure. In this seminar I will review some of the steps that led in the first half of the last century to the quantum-mechanical calculation of the natural width of spectral lines. In the first place I will introduce the model put forward by Lorentz (1890's) to describe the interaction atom/radiation field in terms of harmonic oscillators (Lorentz oscillators). Then a necessary account of both the theory of radiative transitions by Einstein (1917) and the equivalence between the absorbing atoms and an ensemble of Lorentz oscillators stated by Ladenburg (1921) will be given. Finally I will consider the fundamental contribution by Weisskopf and Wigner (1930), who showed that a bound level of an unperturbed atom has a finite width determined by the lifetime of the level, according to the energy-time uncertainty established by the Heisenberg's principle.

contact: Carlo Morossi

Wed, AUG 31, 2016
SPEAKER: Srdjan Kotush (Swinburne University of Technology, Hawthorn,  AU)
TITLE: Highest precision limit on variation in the fine-structure constant from a single quasar absorption system
ABSTRACT: In the last 15 years, studies of velocity shifts between metal transitions observed in high-resolution quasar spectra with the largest optical telescopes identified possible evidence for variation in the fine-structure constant, α. Recent ‘supercalibration’ techniques have shown that these spectra likely have significant systematic distortions in their wavelength scales that undermine the α measurements. We have selected the brightest southern quasar HE 0515-4414 at zabs > 1 to obtain the highest S/N spectrum available, achieve the smallest statistical error on Δα/α to date and, most importantly, allow systematic effects to be tracked and corrected with high fidelity. For this purpose we have combined HE 0515-4414 spectra observed with UVES/VLT over 10 years, producing an extremely high signal-to-noise ratio spectrum (peaking at ~250 pix-1). This provides the most precise measurement of ∆α/α from a single absorption system to date, ∆α/α = −1.42 ± 0.55stat ± 0.65sys parts per million (ppm). This has a similar precision to previous measurements from large samples of ~150 absorption systems. This measurement is corrected for the largest systematic effect present in all (except one) previous measurements, the long-range wavelength distortions, which would add 10 ppm to the systematic error budget. We also discuss how our methods for correcting the spectra, in this case, can be applied to future spectra, in particular from the upcoming ESPRESSO spectrograph. Our spectrum also offers a preview of the data quality available from the next generation of telescopes, but also the problems that must be overcome to access the full photon-limited precision.

                                                                                                                                                                  contact: Paolo Molaro

Wed, JUN 15, 2016 
SPEAKER: Roberto De Propris (Tuorlan Observatorio, Piikkiö, FI)
TITLE:  The evolution of galaxy structure in the CLASH clusters (and beyond)
ABSTRACT: We use HST images in rest-frame B and R for 25 CLASH clusters and four clusters at z > 1 to measure the evolution of galaxy structure (effective radius, Sersic indices and axial ratios) and the colour gradients for red sequence cluster members. Our results show that at z > 0.8 there is a significant contribution from red disks, resembling ‘anemic’ spirals, on the red sequence. While massive and bright galaxies appear to be classical ellipticals, the fainter systems around L* and fainter appear to be quiescent or recently quenched spirals. We show that these galaxies have large, age-related, colour gradients at z > 1 that disappear at z < 0.6, leaving the pristine metallicity gradient belonging to the spheroids. This suggests that the young disks were quenched at z~1.5 and have disappeared by z ~0.6 at least. Our results imply that possibly all ‘ellipticals’
may contain residual disks that have largely faded and are hidden at lower redshifts.

contact: Andrea Biviano

Wed, JUN 8 , 2016 
SPEAKER: Michaela Hirschmann (Institut d'Astrophysique de Paris - CNRS, Paris, FR)
TITLE: The impact of energetic phenomena on the evolution of galaxies -- a theoretical perspective
ABSTRACT: We present new insights from advanced semi-analytic models (SAMs) and modern cosmological simulations indicating a much more complex interplay between different feedback processes and galaxy evolution than traditionally anticipated. Both, SAMs and large-scale simulations are successful in producing realistic global galaxy populations e.g. capturing the observed anti-hierarchical trend in galaxy growth. For that, stellar feedback can play an important role for regulating the gas content in low-mass galaxies, particularly at high redshifts. Employing advanced high-resolution zoom simulations, we can confirm and extend previous results that different AGN feedback mechanisms can strongly affect the kinematics, stellar content and circum-galactic medium of massive galaxies, e.g. by driving strong gaseous outflows and regulating their insitu star formation. But contrary to the traditional picture, galactic winds from SN explosions and massive stars are also crucial for the stellar mass assembly of massive galaxies, not only significantly delaying early insitu star formation but also strongly affecting the accreted stellar populations at large radii. Successes and limitations of most recent models and perspectives for future improvements will be given.

contact: Gabriella de Lucia

Wed, JUN 1, 2016
SPEAKER: Steven Tingay (IRA-INAF, Bologna, IT)
TITLE: The Square Kilometre Array: science and technology
ABSTRACT: The Square Kilometre Array (SKA) is being designed as the most powerful facility for radio astronomy ever conceived. Consisting of two separate telescopes on two continents (Australia and South Africa) a frequency range of 50 MHz to approximately 14 GHz will be covered, allowing a wide range of astrophysics to be covered. In this seminar, I will briefly introduce the SKA project and describe the instrumentation. I will briefly summarise the broad SKA science case, before focusing on a few areas of high scientific impact, including the Epoch of Reionisation (EoR), cosmology, and high energy astrophysics. In particular, I will attempt to demonstrate the unique contributions that the SKA can make in these areas, alongside other existing and future facilities such as Planck, JWST, E-ELT, Euclid, and the CTA. In particular, to unravel the early stages of galaxy and mass assembly and pin down cosmological evolution, during the EoR and earlier/later, a multi-wavelength approach is required to separate the astrophysics and the cosmology. Organisations that span and harness these facilities and capabilities will be at the forefront of modern astrophysics and cosmology. I propose that INAF is one such organisation. Italy has played a leading role in the definition of the SKA science case, plays an important role in the technical development of the SKA, and has a footprint in almost all the major future astrophysics and cosmology facilities.

contact: Stefano Cristiani

Wed, MAY 25, 2016
SPEAKER: Francesca Zambon (IAPS, Roma, IT)
TITLE:  Asteroid Vesta: An overview after the Dawn mission
ABSTRACT: Vesta, the second largest object in the main asteroid belt of our Solar System, was explored by the NASA Dawn mission for over one year in 2011-2012. Dawn is equipped with the Framing Camera (FC), which provides geological and compositional analysis, the Visible and InfraRed (VIR) mapping spectrometer, which allowed a comprehensive mineralogical mapping of the surface, and the Gamma Ray and Neutron Detector (GRaND), which reveals the elemental composition. A wealth of data acquired by these three instruments allowed for improving the knowledge on the surface and near-surface properties of Vesta.
Based on VIR data acquired in the overall spectral range 0.25-5.1 µm at spatial scales ranging from tens of meters to tens of kilometers, the overall mineralogy of Vesta is consistent with howardite–eucrite–diogenite (HED) meteorites. More specifically, VIR spectra are consistent with a surface covered by a howardite-like regolith containing various proportions of eucrite and diogenite at different locations. Diogenite shows up in localized regions and mostly occurs in the southern polar region within the Rheasilvia impact basin.
I will present an overview of the main scientific results obtained by the VIR instrument at Vesta, both at regional scale and local scale. From March 2015 onwards, the Dawn spacecraft is exploring its other major target, the dwarf planet Ceres. Here the hyperspectral images returned by VIR have already been able to provide important clues about the overall mineralogy.

contact: Paolo Molaro

 

Wed, MAY 18, 2016
SPEAKER:  David Alonso (Oxford University, Oxford, UK) 
TITLE:  Multi-tracer science with optical and radio surveys
ABSTRACT: Thanks to "Stage-IV" experiments, such as the Large Synoptic Survey Telescope or the Square-Kilometre Array, in the next decade we will have at our disposal an unprecedented coverage of the sky, in terms of area, depth and frequency bandwidth. This situation will open the possibility for new and exciting cosmological observables and analysis techniques based on combining observations from different experiments. In my talk I will present a number of such synergies.

contact:  Matteo Viel

TUE, MAY 17, 2016 --- EXTRA SEMINAR
SPEAKER: Ilia Musco (LUTH, Observatoire de Paris, Meudon, FR)
TITLE: Causal nature and dynamics of trapping horizons in black hole collapse
ABSTRACT: In calculations of spherically symmetric collapse to form black holes, trapping horizons make their first appearance either within the collapsing matter or where it joins on to a vacuum exterior. Ones moving outwards with respect to the matter have been proposed for replacing the global concept of an ``event horizon'' in the case of dynamical black holes. Using the Misner-Sharp formalism, we have studied the causal nature of both ingoing and outgoing horizons during collapse of idealised stellar models, with two complementary approaches focusing, respectively, on null-congruence expansion and on the horizon velocity measured with respect to the matter. The stellar models are simplified, but have a physically-motivated pressure, unlike the so-called ``dust'' models, and we find that this plays an important role in general. Comparison between the two complementary approaches leads to some new insights including giving pointers towards possible changes due to quantum effects if energy conditions are violated.

contact: Silvio Bonometto

 

Wed, MAY 11 , 2016
SPEAKER:  Cristiano Porciani (Argelander Institut für Astronomie der Universität Bonn, Bonn, DE)
TITLE: Myth and truth about halo formation in CDM models
ABSTRACT: The conventional wisdom in cosmology is that that cold-dark-matter haloes form out of initial density peaks and continuously accrete matter from the surroundings becoming more and more massive with time. These concepts form the basis of several semi-analytical tools that are regularly used to interpret data from galaxy and cluster surveys and develop galaxy-formation models (e.g. the halo mass function, merger trees, galaxy biasing). Using a suite of numerical simulations, we present thorough tests of the established scenario and show that it is mandatory to introduce new elements in the theory of the gravitational collapse of cold matter.

contact: Pierluigi Monaco

 

THURSDAY, APR 28, 2016 -- 11:30 AM sala ovale 
SPEAKER:  Giovanni Cresci (INAF-Arcetri, Firenze, IT)
TITLE: Blowin' in the wind: feedback from QSO and AGN outflows locally and at high-z 
ABSTRACT: Quasar feedback in the form of powerful outflows is invoked as a key mechanism to quench star formation in galaxies, although direct observational evidences are still scarce, probably because radiatively driven winds are rare as they arise during a short-lived phase. I will present near-IR integral field observations of a sample of high-z QSOs, in which we clearly resolve fast (up to 1500 km/s) extended (up to 13 kpc from the black hole) outflows in the [OIII] lines, whose high velocity and high mass outflow rate are unlikely to be sustained by star formation only. Moreover, Star Formation tracers in some of these objects show that the outflow position is anti-correlated with the star forming regions in the host galaxy, representing the first direct evidences of powerful outflows removing the gas from the host galaxy (`negative feedback'). Evidences of gas depletion in these source are also provided by the direct measurement of molecular gas from PDBI and ALMA observations. However, in one of the objects we also have evidences of the opposite mechanism, star formation triggered at the edges of the outflow ('positive feedback'). Finally, I will present optical IFU observations with MUSE of a sample of nearby AGNs, the MAGNUM survey. These include NGC5643, a local Sy2 galaxies where we find evidences of outflow induced star formation in the nuclear region, further suggesting that positive feedback may be a relevant mechanism in shaping the black hole-galaxy coevolution.

contact: Elena Rasia 

Wed, APR 20, 2016
SPEAKER:  Carlos Martins (Centro de Astrofísica da Universidade do Porto, Porto, PT)
TITLE: Fundamental physics and cosmology in the E-ELT era
ABSTRACT: The observational evidence for the recent acceleration of the universe demonstrates that canonical theories of cosmology and particle physics are incomplete (and possibly incorrect) and that new physics is out there, waiting to be discovered. The most fundamental task for the next generation of astrophysical facilities is to search for, identify and ultimately characterize this new physics. I will highlight the E-ELT's key role in this quest. After a short overview of theoretical motivations for new physics, the discussion will focus on precision spectroscopy tests of fundamental physics and cosmology. I will highlight the current status of these tests and present some forecasts of the improvements that the E-ELT will enable (comparing them to ESPRESSO when appropriate). Time permitting I will also briefly comment on synergies with other E-ELT instruments, and with other facilities such as ALMA and Euclid.

contact: Paolo Molaro

Wed, MAR 23, 2016 
SPEAKER: Dietrich Baade (ESO, Garching, DE)
TITLE: To Be or not to Be: The Star, the Disk, and the Ugly
ABSTRACT: Be stars consist of rapidly rotating B stars surrounded by a Keplerian disk, where the name-giving emission lines form. Pulsationally-driven rotation-assisted outbursts generate the ejecta that build and replenish the disk. The disk life cycle is governed by viscosity. When the central star is inactive, the decretion disk becomes an accretion disk so that Be stars are the brightest and angularly largest laboratories of the universally important disk physics. The talk will focus on the interactions between star and disk.

contact: John Danziger

Thu, MAR 17, 2016 -- EXTRA SEMINAR
SPEAKER: Lauro Moscardini (Universita' di Bologna, Bologna, IT)
TITLE: Looking for Baryon Acoustic Oscillations of Galaxy Clusters
ABSTRACT: Baryon Acoustic Oscillations (BAO) are currently one the most powerful cosmological probe. They exploit the technique of the standard ruler to map the distance-redshift relation to get cosmological constraints. Usually BAO are investigated using wide surveys of galaxies. Here I present the first results of their application to the largest spectroscopic samples of galaxy clusters to date reaching z=0.5.

contact: Pierluigi Monaco

Wed, MAR 16, 2016
SPEAKER: Fabio La Franca (Universita' Roma 3, Roma, IT)
TITLE: Looking for the broad emission lines in AGN2 with deep NIR spectroscopy and the measure of the mass of Intermediate Mass BH
ABSTRACT: According to the current models of galaxy evolution in a hierarchical cosmology, low mass Black Holes (<10^7 Msun) at low redshift contain clues about the formation of the first Black Holes and Galaxies. Moreover, as they extend the dynamic range of the BH-mass/galaxy scaling relations to extreme values, they are very useful in constraining the AGN/Galaxy co-evolutionary models. In the past years, in the framework of the verification of the AGN unified model, there have been several attempts to detect faint broad emission lines in type 2 AGN with both NIR and polarised spectroscopy. We here present the new results from a systematic study performed using deep NIR (VLT and LBT) spectroscopy of a sample of about 40 AGN2, drawn from the complete SWIFT/BAT 70-month hard (14-195 keV) X-ray selected sample. A new virial relation able to measure the BH mass using the broad component of the Paschen Beta line will be presented. Thanks to the above relation we have been able to directly measure, when the BLR has been detected, the BH mass of type 2 AGNs. The implications on the measure of the local Intermediate BH Mass Function will be discussed.

contact: Pierluigi Monaco

Wed, MAR 9, 2016
SPEAKER: Angela Bragaglia (INAF-OABO, Bologna, IT)
TITLE: The contribution of Globular Clusters to the Galactic halo
ABSTRACT: The reliable identification of field halo stars born in globular clusters (GCs) is important to understand the actual contribution of GC stars to the Milky Way halo. Depending on the GC formation mechanism, the contribution may be  minimal,  a mere few per cent, or very important, with more than 50\% (see e.g.  the review in Gratton et al. 2012). I will discuss the possibility of finding stars  lost by GCs by chemical tagging, i.e. using the peculiar chemistry found in GCs  focussing on what has been done with "private" data and mini-surveys (e.g., the FLAMES survey of Galactic GCs done by our group, see Carretta et al. 2009a,b; and Bragaglia et al. 2015 for the last results) and what can be obtained from large scale  observational campaigns, such  as the public high-resolution survey  Gaia-ESO or future surveys.

contact: Carlo Morossi

Wed, FEB 24 , 2016
SPEAKER: Adriana Gargiulo (INAF OABO & Univ. Bologna, BO, IT)
TITLE: A (short) journey in the realm of quiescent galaxies
ABSTRACT: In local universe, passive galaxies represent only ~20% of the total number of galaxies, but contribute for more than 60% to the total mass. As a consequence, the comprehension of the mechanisms driving their stellar mass accretion is a fundamental step to understand the universe we see today. In the last five years, deep HST surveys have given a boost to our knowledge on massive quiescent galaxies, erasing some doubts and opening new ones. In this talk I present some of the recent results, both on local and high-z (z ~ 2) passive galaxies, which allow us to gain insight on and to constrain their stellar mass assembly history.

contact: Andrea Biviano

Wed, FEB 17, 2016
SPEAKER: Filippo Mannucci (INAF Arcetri, FI, IT)
TITLE: What are the progenitors of type Ia Supernovae? 
ABSTRACT: Type-Ia supernovae are important distance indicators, element factories, cosmic-ray accelerators, kinetic-energy sources in galaxy evolution, and endpoints of stellar binary evolution. It has long been clear that a SN Ia must be the runaway thermonuclear explosion of a degenerate carbon-oxygen stellar core, most likely a white dwarf (WD). However, the specific progenitor systems and the processes that lead to ignition have not been identified. Two broad classes of progenitor binary systems have long been considered: single-degenerate (SD), in which a WD gains mass from a non-degenerate star; and double-degenerate (DD), involving the merger of two WDs. New theoretical work has enriched these possibilities with some interesting updates and variants. I'll present significant recent observational progress in addressing the progenitor problem. Two recent, nearby, and well-studied events have been particularly revealing. The observational results are not yet conclusive, but they start to point toward one specific direction.

contact: Pierluigi Monaco
 

Wed, FEB 10, 2016
SPEAKER: Stefania Salvadori (Observatoire de PARIS-CNRS, Meudon, FR)
TITLE: Early cosmic star-formation and metal-enrichment
ABSTRACT: The formation of the first stars brought the infant Universe out of the dark ages and changed its chemical composition by producing the first heavy elements, which were dispersed into the surrounding gas via energetic supernova explosions. Metals, dust, and photons strongly affected the cooling properties of the gas, and hence the subsequent formation of stars and galaxies. In the Local Group, spectroscopic studies of individual stars provide us with the unique opportunity to reveal the chemical enrichment of the interstellar medium when the Universe was less than 1 Gyr old. In this talk, I will review the most recent findings for the chemical evolution of the Local Group, from both theoretical and observational perspectives. I will present new insights on early cosmic star-formation and the properties of the first stars, and show possible connections between local dwarf galaxies and more distant Damped Lyman Alpha systems.

contact: Gabriella De Lucia

Wed, FEB 3 , 2016
SPEAKER: Luciano Burderi (Dip. Fisica, Univ. Cagliari, Cagliari, IT)
TITLE: The quantum clock: a critical discussion on (space-)time
ABSTRACT: We critically discuss the measure of very short time intervals. By means of a Gedankenexperiment, we describe an ideal clock based on the occurrence of completely random events. We show that the minimum time interval dt that this clock can measure scales as the inverse of its size dr. This implies an uncertainty relation between space and time: dr dt >= Gh/(2pi c^4) where G, h, and c are the gravitational constant, the Planck constant, and the speed of light, respectively. We outline and briefly discuss the implications of this uncertainty principle. Finally we will discuss an experiment, that could be mounted on a space station or borne on a balloon, consisting in a very large area detector, capable to investigate (sub)millisecond structures in the prompt emission of Gamma Ray Bursts. We show that energy-dependent time lags in these phenomena could probe the granular structure of the space-time fabric down to the Planck scale.

contact: Pierluigi Monaco

 

Wed, JAN 27, 2016
SPEAKER: Viviana Casasola (INAF-AAO, Arcetri, IT)
TITLE: The resolved star-formation relation in nearby active galactic nuclei
ABSTRACT: I will present the results of a study on the molecular gas spatially resolved star-formation relation for a sample of low-luminosity active galactic nuclei in the context of the NUclei of GAlaxies (NUGA) project. Spatially unresolved studies of the star-formation relation have been and are still useful for characterizing global disk properties, but understanding the mechanisms behind the star formation requires resolved measurements. The recent high-resolution observations are allowing to study the star-formation relation to its intrinsic spatial scale, i.e. the size of giant molecular clouds (~10-150 pc). With our NUGA (PdBI+SMA) CO(1-0), CO(2-1), and CO(3-2) sensitive high-resolution maps on scale of 20-200 pc, I have investigated the correlations and slopes of the star-formation relation as a function of spatial resolution. Here I present the results of this study, as a preview of what's coming with the explosion of ALMA data. I will also mention the Dustpedia project, a Definitive Study of Cosmic Dust in the Local Universe, based on Herschel Space Observatory and Planck Telescope databases.

contact: Valentina D'Odorico

 

Wed, JAN 13, 2016
SPEAKER: Mauro Nanni (ORA Bologna, Bologna, IT)
TITLE:ICT@INAF domande, proposte e criticita'
ABSTRACT: A 2 anni dall'istituzione dell'Unita' Vi della Direzione Scientifica - ICT, molto lavoro e’ stato fatto e molto c’e’ ancora da fare, ma le attivita’ svolte hanno portato gia’ a significative iniziative che coinvolgono colleghi di diverse strutture. Allo scopo di rafforzare questa collaborazione, si illustrera' il lavoro fatto e la roadmap del ICT oltre a raccogliere le richieste ed i suggerimenti direttamente della comunita'.

contact: Riccardo Smareglia

Wed, DEC 16, 2015
SPEAKER: Chiara Feruglio (Scuola Normale Superiore, Pisa, IT)
TITLE: On the role of superwinds in the life-cycle of galaxies
ABSTRACT: The life cycle of galaxies and of their Active Galactic Nuclei (AGN) is regulated by three fundamental processes: (1) gas accretion from the Inter/Circum Galactic Medium (IGM/CGM), (2) galaxy interactions, including major and minor mergers, and (3) feedback, i.e. injection of energy and transport of metals into the ISM/CGM through galactic winds (superwinds). Superwinds are galaxy wide, mass loaded and fast outflows of gas. Energy injection by supernova- or AGN-driven superwinds can heat-up the ISM/CGM, preventing its runaway cooling, thus blocking further SF and gas accretion onto the galaxy. AGN-driven superwinds may indeed be the dominant feedback mechanism for galaxy growth at high stellar masses. Observations suggest that AGN superwinds are common both in the local universe and at larger distances, and that they concern virtually all ISM gas phases. Our current understanding of their role for the cosmological evolution of galaxies is, however, hampered by small sample sizes and various biases. I will discuss the state-of the-art on this topic, together with recent progress obtained through both detailed studies of superwinds in individual sources, and through a statistical approach to large samples.

contact: Valentina D'Odorico

Wed, DEC 9, 2015
SPEAKER: Donatella Romano (OABO-INAF, Bologna, IT)
TITLE: Chemical Evolution of Galaxies — Challenges for stellar evolution and nucleosynthesis theory
ABSTRACT: I will discuss a number of current problems in understanding the chemical evolution of galaxies which have an impact on stellar evolution and nucleosynthesis theory. Special emphasis will be put on the chemical properties of stars in the disc of the Milky Way, for which accurate spectroscopic data for large samples of stars are available.

contact: Francesca Matteucci

Wed, DEC 2, 2015
SPEAKER: Livia Origlia (OABO-INAF, Bologna, IT)
TITLE: Cool giants and supergiants as chemical and kinematic probes of their host stellar systems
ABSTRACT: In this seminar I will present some recent observational facts and open questions regarding the use of cool stellar populations and infrared spectroscopy to probe the kinematics and chemistry of their hosts. I will discuss some state-of-the-art studies of resolved stellar populations in those environments characterized by severe crowding and/or reddening, by using near IR spectroscopy and IFU capabilities with various spectral and spatial resolutions at 8-10m class telescopes. Future breakthrough expected by the next generation of IR spectrographs at the VLT and at the E-ELT will be also highlighted.

contact: Elena Mason

Tue, 24 NOV, 2015 at 11:30AM - extra seminar
SPEAKER: Fulvio Parmigiani (Uni TS & Elettra, Trieste, IT)
TITLE: Science driven requirements for seeded soft X-ray free electron lasers
ABSTRACT: Starting from the archetypal FERMI externally seeded FEL, recent theoretical and experimental progress has shown the possibility of producing fully coherent, variable polarization and tunable, soft-X-ray, ultra-short pulses at high repetition rate. This ultimate achievement will unlock the gate for performing X-ray-based experiments that are qualitatively different from those available at any current or planned X-ray source. Here we will review the experiments and the ideas that represent the science frontier in soft X-ray, time-resolved spectroscopy, coherent imaging and scattering experiments. These studies will lead to an understanding of fundamental dynamics, occurring on the ultrafast time and nanometer spatial scales, needed for addressing a broad range of science essential for resolving our complex and long-term energy challenges, environmentally urgent questions and demanding problems in bioscience and novel materials.

contact: Stefano Borgani
Wed, NOV 18, 2015
SPEAKER: Roberto Maiolino (Cavendish Laboratory, University of Cambridge, Cambridge, UK)
TITLE: Stellar feedback, AGN-driven outflows and starvation: the multiple routes to quench star formation in galaxies
ABSTRACT: Understanding the process responsible for transforming star forming galaxies into passive and quiescent systems is currently one of the hottest topics in astronomy. I will discuss recent observational results probing different mechanisms at work in different galaxies and at different epochs. Multi-wavelength observations have provided clear evidence that powerful starburst-driven and AGN-driven outflows, both locally and at high-z, can remove large amount of gas out of their host galaxies and, therefore, have been suggested to be the main mechanism responsible for quenching star formation in galaxies. However, more detailed observations, along with detailed simulations, have shown that such massive outflows may not be able to completely quench star formation in galaxies. I will show that the analysis of the stellar metallicities in large samples of local galaxies reveals that “starvation" (or sometimes called “strangulation”, i.e. the lack of gas inflows), is actually the primary mechanism responsible for quenching star formation in most galaxies. I will discuss the possible mechanisms responsible for the starvation of galaxies. I will finally discuss that neither of these mechanisms is anyhow enough to keep the galaxy quiescent, and a continuous "maintenance mode" must be present in galaxies to prevent gas returned into the galaxy, by simple stellar evolution, from forming new stars.
contact: Francesca Matteucci
 

Wed, Nov 11 , 2015
SPEAKER: Greg Stinson (Max-Planck-Institut fur Astronomie, Heidelberg, DE)
TITLE: A critical phase in galaxy formation
ABSTRACT: As galaxies grow and evolve, they go through a violent phase of their evolution where intense star formation drives outflows. I will examine this phase using cosmological galaxy formation simulations. The simulations show that starbursts and outflows have implications for many observed properties of galaxies including their gaseous halos, morphology, potential, and star formation history.

contact: Pierluigi Monaco
 

Wed, NOV 4 , 2015
SPEAKER: Enrico Costa (IAPS-INAF Roma, Roma, IT)
TITLE: New opportunities for Astrophysical X-Ray Polarmetry.
ABSTRACT: Polarimetry is a branch of X-Ray Astronomy almost complely neglect for more than 40 years.Recently both NASA and ESA have approved advanced studies on three missions aimed to this subtopics, so that the probability that a mission of Polarimetry will fly within the next 10 years is relatively high. The most performant of the proposed mission is the X-ray Imaging Polarimetry Explorer (XIPE) one of the 3 missions candidate for ESA M4 slot. I present the design of XIPE, its observing capabilities and what we expect to understand about the physics and geometry of X-ray sources, that cannot be explained only by spectroscopy and imaging. I present some predictions on observations of Pulsars, Pulsar Wind Nebulae, SN Remnants, Blazars and other topics of Astrophysics and Fundamental Physics

contact: John Danziger

Wed, OCT 28, 2015
SPEAKER: Niccolo' Bucciantini (INAF-OA Arcetri, Firenze, IT)
TITLE: Pulsar Wind Nebulae: a successful marriage of observations and simulations.
ABSTRACT: Pulsar Wind Nebulae (PWNe) are among the best objects where high energy relativistic astrophysics can be investigated. They are close, well resolved in our observation, and the knowledge derived in their study has a strong impact in many other fields, from AGNs to GRBs. They also behave as a probe of the interior of the surrounding SNR, and their dynamical evolution, can be used to constrain parameters of the SN ejecta, otherwise not accessible. Thanks to a lucky combination of high resolution X-ray imaging (mostly thank to CHANDRA) and the coincidental development of numerical codes to handle the outflow and dynamical properties of relativistic MHD, our understanding of these system have greatly progressed in the last years. I will review how a beautifully coherent picture has developed leading to a commonly agreed paradigm, which has branched outside the field of SNRs themselves. I will also present problems, and future possible developments, showing how PWNe continue to provide us with new phenomenology, to challenge established truths.

contact: Elena Mason

Tue, OCT 13, 2015 at 11:30AM
SPEAKER: Kathrin Altwegg (Center for Space and Habitability, University of Bern, Bern, CH)
TITLE: Living with a comet: highlights from the ROSINA instruments on the European Rosetta mission
ABSTRACT: Rosetta has been at comet Churyumov-Gerasimenko more than a year by now and the ten instruments on board the European Space mission Rosetta are very busy studying the comet nucleus and its coma. The two ROSINA mass spectrometers and the pressure sensor are exploring the volatile and not so volatile material in the coma over a wide range of heliocentric distances. In the talk I will present some of the highlights from ROSINA on board and discuss their first implications and conclusions on the origin of our solar system material.

contact: Marco Fulle & Giovanni Vladilo

Wed, OCT 7 , 2015
SPEAKER: Silvano Molendi (IASF-INAF, Milano, IT)
TITLE: Cluster Cores: past, present and (maybe) future
ABSTRACT: Over the last 15 years we have witnessed impressive progress in our understanding of cluster cores. In this presentation I will give an overview of some of the most significant observational findings and discuss their implications for the physics of cluster cores. If time allows and the audience is willing, I will also say a few word about future prospects.

contact: Stefano Borgani

Wed, SEP 23, 2015 --- SEMINARIO ECCEZIONALE (in italiano)
SPEAKER: Paolo Alberi-Auber
TITLE: L'Obelisco di Augusto in Campo Marzio (Roma, 9 a.C.) e il suo impiego in campo gnomonico-calendariale
ABSTRACT: L’Obelisco di Augusto in Campo Marzio (9 AC) era certamente in connessione con l’Ara Pacis Augustae ma, in una seconda fase progettuale, venne usato per un preciso scopo astronomico-gnomonico-calendariale: quello di verificare la validità del Calendario di Giulio Cesare (46 AC) che fino ad allora era stato male applicato e richiedeva una correzione , che poi effettivamente ebbe luogo. Molte testimonianze storiche oltre ai reperti scavati nel 1979/80 sostengono questa ipotesi. I miei recenti calcoli della declinazione solare a 2000 anni di distanza (J. Meeus) permettono di illustrare nel dettaglio l’uso descritto dalle fonti antiche in una ricostruzione delle ombre della sfera sommitale sulla Linea Meridiana. Sfortunatamente, in un percorso secolare che ho ricostruito nei dettagli, un’ipotesi inattendibile , quella di un enorme Orologio Solare largo 400 metri di cui non si è trovata traccia, si è fatta strada e ha trovato spazio grazie all’errore di un archeologo e al fascino di certe immagini .

contact: Paolo Zoblec
 
Wed, SEP 16, 2015
SPEAKER: Anna Pasquali (Astronomisches Rechen-Institut, Universitat Heidelberg, Heidelberg, DE)
TITLE: Imprints of galaxy evolution on HII regions
ABSTRACT: HII regions are the signpost of the most recent episodes of star formation in a galaxy. Their gas, ionized by their young and massive stars, is commonly used to measure the present-day star-formation rate and gas-phase metallicity of their host galaxy. By means of IFU spectroscopy of about 300 nearby galaxies, the CALIFA survey has identified more than 5000 HII regions across a wide range of galaxy Hubble type, stellar mass, age and metallicity. We have studied the distribution of these regions on the classical Baldwin, Philips & Terlevich's (1981) diagram as a function of their properties first (i.e. ionization parameter, electron density and oxygen abundance), then the properties of their host galaxies. The results indicate that HII regions "keep memory" of the star-formation history and chemical enrichment undergone by their host galaxy.

contact: Gabriella de Lucia

Wed, SEP 9, 2015
SPEAKER: Alexander Beck (University Observatory Munich, Munich, DE)
TITLE: Cosmic magnetic fields - Our knowledge and simulation prospects
ABSTRACT: The entire Universe is permeated by magnetic fields. However, little is know about their origin and evolution through all redshifts. In the recent years, magnetohydrodynamic simulations are emerging and provide first views on the magnetic history of the Universe. In this talk, I will presents fully non-ideal MHD simulation of structure formation and show a possible magnetised hierarchical growth scenario. This scenario assumes magnetic field production within the first stars and collapsed objects and later growth and distribution within galaxies. Depending on the invoked transport mechanisms, magnetic fields can be expelled far into the intergalactic medium in a similar fashion as metals.

contact: Stefano Borgani

Wed, SEP 2, 2015
SPEAKER: Michele Fumagalli (Durham University, Durham, UK)
TITLE: Gas flows as fuel for star formation in distant galaxies: a spotlight on strong absorption line systems
ABSTRACT: The interaction of radiation from distant sources with the intervening medium is an invaluable way to map the distribution and chemical composition of matter in the high-redshift universe. During the past 50 years, however, optically-thick clouds that give rise to Lyman limit systems (LLSs) have received much less attention than the Lyman-alpha forest or the damped Lyman-alpha absorbers (DLAs). Thus, the connection between these absorbers and galaxies still remains for most part elusive. The growing interest in studies of the circumgalactic medium is, however, putting the spotlight on the link between LLSs and galaxies. In this talk, I will present results from ongoing work to constrain the physical properties of LLSs, and I will discuss ways to exploit these absorbers, together with DLAs, as tools for the study of the halo gas and star formation in the high redshift universe.

contact: Valentina D'odorico

Wed, JUL 1 , 2015
SPEAKER: Corrado Perna (Ufficio Trasferimento Tecnologico della Direzione Scientifica - INAF)
TITLE: Our policy for a global outstanding innovation
ABSTRACT: Innovation arises from a creative environment where, new locally developed ideas, might globally be delivered to markets, governments and societies as new solutions able to better meet challenging requirements by means of more effective products, processes, services and technologies. Due to its own mission and skills, INAF is a naturally innovative environment who is also asked to play a global leading role to maximize the Return On national Investments (ROI) allocated to researches on Astronomy and Astrophysics, in order to let the Country to gather benefits of a frontrunner innovation capability. The talk shows an outlook of the INAF’s strategies and tools to achieve such a goal.

contact: Stefano Borgani

Wed, JUN 24 , 2015
SPEAKER: Michal Chodorowski (Copernicus Astronomical Center, Warsaw, PL)
TITLE: Distortions of galaxy clustering in redshift surveys
ABSTRACT: In deep three ­dimensional surveys of galaxies, as the third coordinate of a galaxy's position in space its redshift is adopted. Density inhomogeneities in the Universe induce deviations from the simple Hubble velocity flow of galaxies. As a result, redshift is not a perfect estimator of the true distance and maps of the galaxy distribution in REDSHIFT SPACE give a distorted view of their spatial distribution in real (configuration) space. In particular, the two ­point (auto­)correlation function of galaxies is anisotropic in redshift space. Interestingly, the amount of anisotropy depends on the rate of growth of density fluctuations in the Universe, which is different in dark energy and modified gravity cosmologies. A measurement of the growth rate from galaxy redshift surveys can thus serve as a method to differentiate between various competing cosmological theories, explaining the current acceleration of the Universe expansion in a qualitatively distinct way. To achieve this goal, very accurate estimates of the growth rate from observations, as well as precise theoretical models of the correlation function of galaxies in redshift space are needed. The accuracy of the measurements steadily increases with time. However, despite of numerous attempts over the last two decades, there is still no model which satisfactorily predicts isocontours of the correlation function in redshift space. After describing a few most popular models existing in the literature, I will briefly present my recent work on the subject. My model has more realistic physical assumptions and in consequence fares much better than the former when compared to the results of N­body simulations.

contact: Matteo Viel

Wed, JUN 17, 2015
SPEAKER: Ruth Durrer (Universite' de Geneve, Geneve, CH)
TITLE: Large scale structure of the Universe: the angular power spectrum and bispectrum
ABSTRACT: In the measured angular and redshift distribution of galaxies we see not only the density fluctuations of the matter distribution but also effects from peculiar velocities, from lensing and other relativistic effects. I shall discuss how these enter the power spectrum of the galaxy distribution in linear perturbation theory and the bispectrum in second order perturbation theory. I shall also discuss possible observational strategies which may help to measure some of the interesting relativistic contributions.

contact: Enea di Dio

Mon, JUN 15, 2015 @ 11:30 AM -- EXTRA SEMINAR
SPEAKER: Chiara Tonini (Swinburne University of Technology, Hawthorn, AU)
TITLE: Hierarchical galaxy formation and its manifestations in early-type galaxies.
ABSTRACT: Bulges and elliptical galaxies are showing a growing complexity in their structure and physical properties, highlighted by the new state-of-the-art IFU surveys. There has been tension between theory and observations regarding the interpretation and understanding of these objects. New, more sophisticated physical recipes in theoretical galaxy formation models allow for a more detailed and successful comparison with the recent observations, and highlight interesting connections between morphology, dynamics and star formation history of elliptical. I will present the results of one such model, regarding the mass-size relation, the metallicity, the stellar population content, and the different channels of galaxy assembly that govern the evolution of elliptical galaxies.

contact: Gabriella de Lucia
 
Wed, JUN 10, 2015
SPEAKER: Wang Lan (NAOC - China National Astronomical Observatories, Beijing, CN)
TITLE: Galaxy formation in warm dark matter cosmology
ABSTRACT: The mass of the Universe is dominated by dark matter, a type of matter that only has gravitational interaction. However, we know little about the nature of dark matter. In particle physics, sterile neutrino is a commonly proposed candidate of dark matter, which belongs to warm dark matter phenomenologically. Compared with the current standard cold dark matter cosmology, warm dark matter predicts differently on small scales of the Universe. We develop cold and warm dark matter N-body cosmological simulations with high resolution, to study the numerical effect of warm dark matter simulation in detail. Combined with semi-analytic models of galaxy formation, we compare the predictions of warm and cold dark matter cosmology on various properties of the Universe and on various scales, in order to break the degeneracy between cold and warm dark matter models, and hope to find out the best observations to constrain the phenomenological property of dark matter.

contact: Gabriella De Lucia

Mon, MAY 25, 2015 -- at 11:30 AM
SPEAKER: Tirthankar Roy Choudhury (National Centre for Radio Astrophysics, Pune, IN)
TITLE: Constraining Reionization History of the UniverseBSTRACT: Reionization of neutral hydrogen by first stars is an important event in the history of our Universe. Studying reionization can help us understand the nature of first stars and their environments. The talk will focus mainly on current observational constraints on reionization history and how to construct theoretical models which can explain these observations. Some future prospects for detecting the epoch of reionization using low frequency instruments will also be discussed.

contact: Matteo Viel & Francisco Antonio Villaescusa Navarro

Wed, MAY 13 , 2015
SPEAKER: Chiaky Kobayashi (Univ. of Hertfordshire, Hatfield, UK)
TITLE: Cosmic chemical enrichment with AGN feedback
ABSTRACT: I show chemical evolution of galaxies in our cosmological, hydrodynamical simulations with the feedback from active galactic nuclei (AGN). We have applied a new model for the formation of black holes motivated by the first star formation, in contrast to the merging scenario of previous works. The model parameters are determined from observational constraints, namely, the cosmic star formation rate history, black hole mass-galaxy mass relation, and the size-mass relation of galaxies. We then obtain better agreement with the observed down-sizing phenomena, namely, the colour-magnitude relation, specific star formation rates, and the alpha enhancement of early type galaxies. In massive galaxies, AGN-driven outflows transport metals into the circumgalactic medium and the intergalactic medium, which is important for a large-scale chemical enrichment in the Universe. Smaller galaxies can get external enrichment from nearby AGN depending on their environment. Nonetheless, these metallicity changes are negligible, and the mass-metallicity relations, which are mainly generated by supernova feedback at the first star burst, are preserved. The mass-metallicity relations evolve showing a steeper slope at higher redshifts. Within galaxies, stellar metallicity radial gradients evolve depending on the their merging histories, while gas-phase metallicity gradients are flattened by AGN feedback. It is possible to untangle the formation histories of galaxies from the observations of on-going spectral and IFU surveys.

contact: Gabriella de Lucia
 

Mon, MAY 11, 2015 -- EXTRA SEMINAR
SPEAKER: Stefano Camera (University of Manchester, Manchester UK)
TITLE: Cosmology on the Largest Scales
ABSTRACT: Ultra-large cosmic scales supply a wealth of information most valuable for strengthening our knowledge of the Universe. For instance, they can teach us about the physical processes at play during the inflationary epoch, or enable us to either further confirm or rule out Einstein's theory of general relativity. This is because: on the one hand, there are relativistic corrections to the Newtonian prediction that only become important on extremely large scales; and, on the other hand, those scales may hide signatures of modifications to gravity. However, the largest cosmic scales have hitherto proven to be utterly difficult to access. Here, I review the current endeavour on reaching such ultra-large scales with present and planned experiments, with a view on primordial non-Gaussianity as a well-known representative of a non-standard large-scale effect.

contact: Matteo Viel

 

Wed, MAY 6, 2015
SPEAKER:Piercarlo Bonifacio (GEPI, Observatoire de Paris, Meudon, FR)
TITLE: Carbon enhanced metal-poor stars: new insights from the TOPoS project
ABSTRACT: It has been known for the last twenty years, among metal-poor stars the farction of carbon-enhanced metal poor stars (CEMP, [C/Fe]> +1) increases with decreasing metallicity. I will present new results from the TOPoS project, including three newly discovered CEMP stars with metallicity below -4.5, rasing to a total of nine the known metal-poor stars in this metallicity regime. Eight out of nine of these stars are CEMP. Five of these nine stars are unevolved (TO or SGB) and only one has a measured Li abundance, about 0.4 dex below the Spite plateau. A low lithium abundance seems to be a general characteristic of these stars. Another striking characteristic of the extremely metal-poor stars is the very low scatter in the [X/Ca] ratios for all elements heavier than Si, in spite of the fact that they span 3 orders of magnitude in Fe (or Ca) abundance. Our proposed scenario for the formation of the first generations of stars, is the formation of several massive stars in a mini-halo, at least one of which should explode as a faint supernova, to produce the excess carbon. I will finally discuss future perspectives for the search of and analysis of EMP stars.

contact: Paolo Molaro

 

Wed, APR 29, 2015
SPEAKER: Hans Ludwig (Zentrum für Astronomie, University of Heidelberg, DE)
TITLE: The 3D model atmosphere code CO5BOLD: methodology and tales of application
ABSTRACT: will give a description of the methodology behind the CO5BOLD 3D model atmosphere code which is in part developed at the Center of Astronomy at Heidelberg University. The code is build to construct high-fidelity models of the surface layers of late-type stars. For this, (magneto-)hydrodynamics and radiative transfer are main ingredients. I will describe projects which illustrate CO5BOLD's capabilities, mainly revolving around high resolution spectroscopy. One cracking story is connected to recent laboratory measurements of stellar opacities with the "Z-machine".

contact: Paolo Molaro

Wed, APR 22 , 2015
SPEAKER: Saleem Zaroubi (Kapteyn Astronomical Institute, Groningen, NL)
TITLE: Upper limits on the Epoch of Reionization from LOFAR
ABSTRACT: The Epoch of Reionization is one of the least explored epochs in the history of the Universe. The redshifted 21 cm line from neutral hydrogen emitted during this epoch is the most promising probe for exploring it. To date there are a number of low frequency radio telescope that are aiming at detecting this radiation. The LOw Frequency ARray, LOFAR, which a European telescope centred in the Netherlands, has started collecting data on December 2012. I will discuss the current status of the experiment and the main results coming out of it.

contact: Pierluigi Monaco

 

Wed, APR 15, 2015
SPEAKER: Alessandro Melchiorri (INFN, University of Rome "La Sapienza")
TITLE: Latest results from Planck and their implications for cosmology
ABSTRACT: In this brief talk I will present some of the new results coming from the Planck 2015 data release focusing on the new, stringent, constraints on cosmological parameters and their compatibility with independent cosmological observables. The new data from Planck are consistent with the six-parameter inflationary LCDM cosmology. From the Planck temperature and lensing data, for this cosmology we find a Hubble constant, H0= (67.8 +/- 0.9) km/s/Mpc, a matter density parameter Omega_m = 0.308 +/- 0.012 and a scalar spectral index with n_s = 0.968 +/- 0.006. Combined with Planck temperature and lensing data, Planck LFI polarization measurements lead to a reionization optical depth of tau = 0.066 +/- 0.016. Combining Planck with other astrophysical data we find N_eff = 3.15 +/- 0.23 for the effective number of relativistic degrees of freedom and the sum of neutrino masses is constrained to < 0.23 eV. We find no evidence for isocurvature perturbations or cosmic defects. The equation of state of dark energy is constrained to w = -1.006 +/- 0.045. We investigate annihilating dark matter and deviations from standard recombination, finding no evidence for new physics. The Planck results for base LCDM are in agreement with BAO data and with the JLA SNe sample. However the amplitude of the fluctuations is found to be higher than inferred from rich cluster counts and weak gravitational lensing. Apart from these tensions, the base LCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.

contact: Pierluigi Monaco

 

Wed, APR 8, 2015
SPEAKER: Massimo Della Valle (INAF-NA, IT)
TITLE: Supernovae shed light on Gamma-Ray Bursts
ABSTRACT: We review the observational status of the Supernova/Gamma‐Ray Burst connection. Most observations collected in the last 15 years show that long duration Gamma‐ray Bursts are associated with broad lines SNe‐Ibc, although a few remarkable exceptions do exist. Current estimates of SN and GRB rates yield a ratio GRB/SNe‐Ibc less (or much less) than 3%.

contact: John Danziger

Wed APR 1, 2015
SPEAKER: Ferdinando Patat (ESO, Garching, DE)
TITLE: Studying supernova explosion asymmetries with spectropolarimetry
ABSTRACT: Linear spectropolarimetry provides unique geometrical information on an astrophysical source. For extragalactic stellar objects this is probably the only technique that can probe the geometry down to spatial scales out of reach for any other method, including interferometry. This is of particular interest for the study of supernova explosions and their asymmetries, of which we are only starting to have some insight. In my talk I will review the results of SN spectropolarimetry and their implications on our understanding of the explosion mechanism for the various SN types. I will close showing some recent results of a polarimetric study of extra-galactic dust along the lines-of-sight to bright supernovae and anticipate some further work in this field.

contact: Elena Mason

 

Wed, MAR 11, 2015
SPEAKER: Andrea Biviano (OATS)
TITLE: CLASH-VLT: the internal structure of galaxy clusters
ABSTRACT: CLASH-VLT is a VLT/VIMOS Large Programme carrying out a spectroscopic campaign on 13 massive galaxy clusters at a median redshift of 0.4. Upon completion, it will provide spectra and redshifts for ~7000 cluster members. I describe some preliminary results from this programme, concentrating on two topics: 1) the internal dynamics of galaxy clusters and 2) the mass function of cluster member galaxies. In 1), I present results on the cluster mass profiles, the orbits of galaxies inside clusters, and the pseudo-phase-space density profile, to set constraints on the mechanisms of formation and evolution of clusters and of cluster galaxies and on the nature of the dark matter. In 2) I investigate the environmental dependence of the mass function, to set constraints on the evolution of cluster galaxies and the formation of the intra-cluster light.

contact: Andrea Biviano

 

Wed, MAR 4, 2015
SPEAKER: Elena Rasia (OATS)
TITLE: Value of Simulations for Galaxy Cluster Cosmology
ABSTRACT: Investigating cluster properties is crucial to validate our knowledge of the fundamental physical processes regulating the formation and evolution of cosmic structures and the interaction between constituents of the universe. In vision of future large cosmological cluster-based surveys, I will review our effort in establishing a robust theoretical framework to be used for the interpretation of the large amount of data we will receive from the sky.

contact: Stefano Borgani

 

Wed, FEB 25, 2015
SPEAKER: Roland Diehl (MPE, Garching, DE)
TITLE: "Gamma-rays from supernovae: Recent lessons and puzzles"
ABSTRACT: Supernova light is powered by radioactive decay of short-lived isotopes which are created from nuclear fusion reactions during the supernova. Radioactive decay produces characteristic gamma-ray lines, and their observation has been a goal of gamma-ray astronomy since first gamma-ray telescopes were built. Now, with SN2014J as the most-nearby supernova of Type Ia since 40 years, for the first time the gamma-rays characterising the radioactive decay chain following production of 56Ni have been observed with INTEGRAL. We will discuss these observations and their implications as well as remaining puzzles. We will also discuss other related gamma-ray line observations from supernova nucleosynthesis.

contact: John Danziger

Fri, FEB 20, 2015 - 11:30 AM -- EXTRA SEMINAR
SPEAKER: Tommaso Treu (UCLA, LA, CA/USA)
TITLE: Finding the first galaxies with a magnifying GLASS
ABSTRACT: How and when did galaxies reionize the universe (if they did)? I will present recent observational results from two projects aimed at answering this question by finding and characterizing the first galaxies. The first project (BORG) aims to find the brightest galaxy candidates above z=7, most suitable for spectroscopic follow-up. The second project (GLASS) exploits the magnifying power of foreground clusters of galaxies and the spectroscopic capabilities of HST to measure spectra of galaxies from the epoch of cosmic reionization to z=0.5. I will summarize some highlights and their implications for our understanding of the sources of reionization. If there is time, I will describe a new technique to measure black holes masses at cosmological redshifts, thus providing insights into the alternative potential source of reionizing photons.

contact: Stefano Borgani

 

Wed, FEB 18, 2015
SPEAKER: Marco Saitta (Pierre & Marie Curie Uinv. Paris, FR)
TITLE: Miller experiments in atomistic computer simulations
ABSTRACT: The celebrated Miller experiments reported on the spontaneous formation of amino-acids from a mixture of simple molecules reacting under an electric discharge, giving birth to the research field of prebiotic chemistry. However, the chemical reactions involved in those experiments have never been studied at the atomic level. Here we report on the first ab initio computer simulations of Miller-like experiments in the condensed phase. Our study (A.M. Saitta & F. Saija, PNAS 111, 13768 2014), based on the recent method of treatment of aqueous systems under electric fields and on metadynamics analysis of chemical reactions, shows that glycine spontaneously form from mixtures of simple molecules once an electric field is switched on and identifies formic acid and formamide (Saitta et al., PNAS, January 2015) as key intermediate products of the early steps of the Miller reactions, and the crucible of formation of complex biological molecules. This work, which has received considerable attention both from the specialized scientific media and the mainstream large public press(Saitta et al., PNAS, January 2015) might have a relevance in geochemistry, as electric fields are naturally present at mineral surfaces, suggesting a potentially crucial role in abiotic chemistry of both the primordial and the modern Earth.

contact: Valentina D'Ododrico

Wed, FEB 11, 2015
SPEAKER: Veronica Biffi (OATS)
TITLE: The bright side of galaxy
ABSTRACT: Galaxy clusters can be a very powerful source of information for both cosmology and astrophysics, especially if results from both observations and numerical simulations are combined to this scope. In particular, the intra-cluster medium (ICM) is an optimal target for this, since it represents about 80 per cent of the visible, baryonic matter in clusters. Here, I will present how numerical simulations can be used to produce synthetic X-ray data, which makes the comparison between simulated clusters and real ones more faithful. In this way, we can address a number of interesting issues, such as the reconstruction of the ICM temperature distribution via spectral analysis, the investigation of scaling relations among global properties or the characterization of the gas non-thermal velocity field. This approach can be very useful to constrain the success of the numerical modeling, but also to predict the capability of up-coming X-ray instruments (such as Athena) to capture the observable signatures of the underlying physical processes taking place in clusters.

contact: Stefano Borgani

Wed, JAN 28, 2015
SPEAKER: Nicolas Bouche (CNRS/IRAP Toulouse, FR)
TITLE: The role of gas flows in regulating star-forming galaxies
ABSTRACT: Galaxies form stars with low efficiencies, as on average only 10% of the baryons are inside the haloes of galaxies. Galactic super-winds are often invoked to explain this fundamental problem in galaxy formation. Recently, galaxy scaling relations such as the main sequence between SFR and M* and the MZR relation have opened new insights on understanding the balance between accretion and outflows. I will review these aspects in light of the most recent constraints on accretion and on outflows using background quasars.

contact: Valentina D'Odorico

Wed, JAN 21, 2015
SPEAKER: Benedetta Ciardi (MPA Garching, DE)
TITLE: Cosmic Reionization: Theoretical Modeling and Challenging Observations
ABSTRACT: With the advent of radio telescopes such as LOFAR, MWA, PAPER etc, a new observational window on the high-redshift universe has been opened. More specifically, we expect in the near future to be able to detect for the first time the 21cm signal from the diffuse Intergalactic Medium (IGM) prior to its reionization and thus probe the "dark ages". In this talk I will discuss about the theoretical modeling of the reionization process, the observability of the associated 21cm signal and the efforts ongoing within the LOFAR Epoch of Reionization Working Group.

contact: Valentina D'Odorico

Mon, JAN 19, 2015 -- EXTRA SEMINAR
SPEAKER: Lucio Crivellari (INAF-OATS, IAC)
TITLE: A numerical laboratory for computational astrophysics: new developments
ABSTRACT: Our project to set up a laboratory for computational astrophysics arose some ten years ago as the natural evolution of our iterative sequential approach to the stellar atmosphere problem, which constitutes a paradigm for the numerical solution of non-local and non-linear problems. The aim of the laboratory is to get at hands a benchmark to ascertain the quantitative effects on the structure of a stellar atmosphere (and by the way on the diagnostics of the stellar properties) brought about by each one of the intervening specific physical processes. In other words, to yield a tool to perform experiments through numerical computation. Along all these years the outcome of the of the laboratory has been a successful study of the overall energy balance in the outer stellar layers when radiative transfer at the frequencies of the most opaque continua and spectral lines is duly taken into account. After a hibernation period a renewed push came recently from the interest shown by the stellar astrophysics group at INAOE (Tonantzintla, Mexico). Hence my wish to let the OAT colleagues know about the new research lines we are going to carry on in the next future. Specifically, to improve the computation of the opacities, both for continua and spectral lines, in order to achieve a better determination of the thermodynamic coefficients and the equation of state for stellar atmospheres and astrophysical plasmas.For the sake of those who may not be aware of the laboratory project, I consider it will be opportune to recall its essential outlines.

contact: Lucio Crivellari

Wed, JAN 14, 2015
SPEAKER: Stefano Zibetti (INAF-Arcetri)
TITLE: (How) do we understand galaxy stellar masses?
ABSTRACT: In my seminar I will summarize how spectral energy distribution (SED) fitting techniques can be used to estimate the stellar mass in galaxies, in particular based on optical and near infrared photometry and spectroscopy. Special attention will be paid to critical assumptions, uncertainties and methodological pitfalls. I will then introduce the SteMaGE-FP7 project ("Towards an understanding of the role of StellarMass in Galaxy Evolution"). I will present some early results concerning stellar population synthesis models and their application to the CALIFA integral field spectroscopic sample, whereby stellar mass maps are derived and used to study the galaxies' structure and dynamics.

contact: Fabio Fontanot

Wed, JAN 7, 2015
SPEAKER: Gabriele Cescutti (AIP Postdam, DE)
TITLE: The nature of the first Stars: the point of view of the neutron capture elements ABSTRACT: In the last years our group has found that many chemical anomalies observed in very metal-poor halo stars in the light elements suggest the first stellar generations to have been fast rotators (spinstars). Recently, theoretical computations have found that spinstars can also play a role in the chemical enrichment of neutron capture elements providing a early contribution of s-process. By means of a stochastic chemical evolution model, it is possible to identify the spinstars s-process contribution as the missing component responsible for the spread in the ratio between light (Sr) to heavy (Ba) neutron capture elements. A specific distribution is predicted for the isotopic ratio of Ba in halo stars and this imprint could be the smoking gun of the role played by spinstars in the spread of [Sr/Ba] ratio. In this context, regarding the still unknown origin of the complementary r-process component, three possible sites are tested: the neutron star mergers, the electron capture supernovae and the magneto rotational driven supenovae; only further investigations in different Galactic component, as the bulge, will enable us to constrain the real site.

contact: Francesca Matteucci

 

Wed, Dec 12, 2014, 11:30 AM -- EXTRA SEMINAR

SPEAKER: Elena Giusarma (INFN,Univerista' La Sapienza, Roma, IT)
TITLE: Implications of cosmological observations on neutrino and axion properties
ABSTRACT: One of the great puzzles related to the ΛCDM model is the nature of the dark matter (DM) component. In standard cosmology, hot, thermal relics are identified with the three light, active neutrinos but the existence of extra hot relic components, as sterile neutrino species and/or thermal axions are also possible. In this work I will illustrate the implications of neutrino properties on cosmological observables and I will analyse the constraints on the three active neutrino masses, extending the analyses to possible scenarios with additional hot thermal relics, as sterile neutrino species or axions, using the available cosmological data.

contact: Matteo Viel

Wed, Dec 10, 2014
SPEAKER: Klaus Dolag (Universitäs Sternwarte, Muenchen, DE)
TITLE: The Magneticum Pathfinder Simulations ABSTRACT: Upcoming astronomical surveys and instruments like Planck, SPT, PanStars,DES, Euclid, LOFAR, eRosita and many more will need a theoretical counterpart in form of simulations which follow the formation of cosmological structures in so far unaccomplished detail, taking into account enough physical processes to allow a self consistent comparison to observations at multiple wavelength and throughout the entire epoch of structure formation. I will report on preliminary results from a recent simulation campaign, where we followed the formation of cosmological structures in so far unaccomplished detail, performing a large set of cosmological, hydrodynamical simulations covering up to Gpc^3 volumes, taking into account enough physical processes (star- formation, chemical enrichment, AGN feedback) to allow a self consistent comparison to observations at multiple wavelength.

contact: Stefano Borgani

Wed, DEC 3, 2014
SPEAKER: Claudia Cicone (Cavendish Laboratory, University of Cambridge, UK)
TITLE: Powerful quasar-feedback in local and very distant (U)LIRGs
ABSTRACT: Understanding the negative feedback mechanisms responsible for regulating and quenching star formation in galaxies, represents a crucial step in solving some of the major open problems in galaxy formation and evolutionary models. In particular, "quasar-mode" negative feedback is often invoked by these models to prevent massive galaxies from overgrowing and to account for the "red-and-dead" properties of massive local and high redshift (z ~ 2) galaxies. The recent discovery of powerful and large-scale outflows of molecular gas in several local (U)LIRGs constitutes a major breakthrough in this field. I will present our latest study (Cicone et al. 2014a) in which we exploit CO(1-0) interferometric observations to make a significant step forward in understanding the properties of massive molecular outflows, their connection with the central AGN and with the ongoing starburst and their profound feedback on the host galaxy. I will also show new exciting results on the quasar-feedback mechanisms in action in the very early Universe, presenting recent interferometric follow-up observations of the extremely massive and extended quasar-driven outflow detected in a quasar-host HyLIRG at redshift z=6.4 using the [CII]158 $\mu$m emission line (Maiolino et al. 2012, Cicone et al. 2014b).

contact: Stefano Cristiani

 

Wed, NOV 26, 2014
SPEAKER: Umberto Maio (INAF-OATS)
TITLE: Observables of the primordial Universe
ABSTRACT: Results from numerical simulations of primordial structures in the first billion years will be presented and their implications on cosmic observables (such as, star formation rate densities, stellar mass densities, luminosity functions) will be discussed. The effects of a wide range of parameters, including different background cosmological models for dark matter, will be explored and expectations for next-generation instruments will be outlined.

contact: Umberto Maio

 

Mon, NOV 17, 2014
SPEAKER: Gary Mamon (Institut d'Astrophysique de Paris)
TITLE: Compact groups of galaxies: their nature, properties and assembly history
ABSTRACT: Compact groups of galaxies are selected to be nearby, isolated, very dense systems of 4 or more galaxies in a range of 3 magnitudes. Their high densities and low velocity dispersions make them the ideal sites for galaxy interactions and mergers, and the present-day massive galaxies may have assembled within compact groups. Yet, half the galaxies in the popular, visually selected, Hickson catalog are spiral, with no statistical signs of galaxy mergers or luminosity segregation. This has led to a debate on whether compact group samples are strongly contaminated by chance alignments of galaxies along the line of sight. I will address the nature of compact groups through the use of mock compact group catalogues extracted from the outputs of semi-analytical models of galaxy formation, themselves run on the halo merger trees of the Millennium cosmological simulations. The use of such mock compact groups allows the quantification of the fraction of compact groups that are chance projections in comparison to those that are physically dense in 3D. The mock compact groups are roughly 10 times more frequent than observed, suggesting a strong incompleteness of the Hickson catalog. I will present the properties of a new, complete, sample of compact groups, extracted from 2MASS in a similar, but automatic fashion as the Hickson catalog. I will highlight the strong differences between the 2MASS-selected compacts groups and the Hickson sample and ask whether star forming galaxies have normal specific star formation rates, are bursty, or anemic. Finally, I will study the mass assembly of compact groups, using the semi-analytical models to compare different possible formation channels.

contact: Andrea Biviano

Wed, NOV 12, 2014
SPEAKER: Robert F. Carswell (Institute of Astronomy, University of Cambridge, UK)
TITLE: Unravelling the element abundances and ionization structure in intervening QSO absorbers
ABSTRACT: Normally the widths of the saturated Lyman absorption lines make it difficult to determine heavy element abundances for different components in a QSO absorber. We suggest how a mixture of velocity structure and ionization modelling may be used to separate components, and find a range of metallicities within an absorption complex which has been studied in detail. The general applicability of, and potential problems with, this sort of analysis is discussed. We also note a source of bias which could lead to overestimates of the heavy element abundances in some systems (particularly the so-called sub-DLAs).

contact: Tae-Sun Kim

Wed, NOV 5, 2014
SPEAKER: Franco Vazza (Hamburger Sterwarte, Universität Hamburg, DE)
TITLE: The magnetism in the cosmic web from simulations and looking towards future observations
ABSTRACT: Magnetic fields are nowadays routinely observed in galaxies and galaxy clusters, while little is known about their distribution in cosmic filaments and for most of the cosmic web. However, the latter potentially carries information about the origin of cosmic magnetism, as it should relate with early cosmological epochs. I will show what can be presently done to follow the growth of magnetic fields in the cosmic web using cosmological simulations, and discuss how this can be used to study the detectability of the cosmic web with future (or incoming) radio facilities, as well as to study the propagation of ultra high-energy cosmic rays in the Universe.

 

contact: Matteo Viel

 

Wed, OCT 29, 2014
SPEAKER: Robert Ben Metcalf (Università of Bologna, IT)
TITLE: Gravitational Lensing
ABSTRACT: Gravitational lensing is becoming an important tool in astrophysics and cosmology. It has been used to study everything from the structure of quasars to the evolution of dark energy. I will review some of these successes and describe future prospect for gravitational lensing in the age of Euclid and SKA. The number of strong gravitational lenses in particular is expected to increase by two orders of magnitude in the not so distant future. I will talk about the issues of finding such rare events in large data sets and how to use them once they are found

 

contact: Umberto Maio

 

Wed, OCT 15, 2014
SPEAKER: Carla Maria Coppola (Chemistry Department, Bari University, IT)
TITLE: Primordial H2 formation in the early universe
ABSTRACT:The increasing sensibility of space missions devoted to Universe exploration at cosmological scales requires an accurate description and modeling of chemical and physical conditions present at high redshifts epochs. In this talk, non-equilibrium features of molecular processes occuring in the primordial plasma will be investigated. In particular, vibrational distribution functions, excitation temperatures and distortion photons due to radiative cascade of H2 on the CMB spectrum will be described.

 

contact: Paolo Molaro

 

Wed, OCT 8, 2014
SPEAKER: Luca Stringhetti (INAF-MI, IT)
TITLE: The System Thinking in INAF: A personal view of the status of system thinking application in INAF
ABSTRACT: This talk will present a personal view of how the way to do projects in astrophysics (and not only in this field) has changed in modern times and how a better applications of a system thinking can help our daily work effectively. We believe that in INAF we do a lot of system thinking, even if sometimes we do not know, so the problem is not doing more, but doing better. Lean principles, so well used in many different applications since the '60, have found in recent years some effective examples in innovation applications. In this talk we will give a short presentation on the motivation to start a cooperation with Università Bocconi di Milano on an application of Lean principles in INAF. We will also present the results of the survey conducted in november 2012 in "Macroarea 5", survey conducted in collaboration with Bocconi, and we discuss with you about conclusions and possibly ways.

contact: Andrea Zacchei