Coming Seminars

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

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

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

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

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.


Wed, JUN 20, 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 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


Wed, JUL 11, 2018 [during summer break]
SPEAKER: Paul Niladri (IUCAA: Inter-University Centre for Astronomy and Astrophysics, Pune, IN)

contact:  Pierluigi Monaco


SPEAKER: Enrica Iodice (INAF-OANA, Napoli, IT)
TITLE: Stellar halos and low surface brightnees features in the galaxy outskirts from deep VST surveys
ABSTRACT: In the recent years, a big effort was made to develop deep photometric surveys aimed at studying galaxy structures down to the faintest levels of surface brightness of mu_g~27-30 mag/arcsec^2 (e.g. the NGVS by Ferrarese et al. 2012, ApJS 200, 4; Duc et al. 2015, MNRAS 446, 120; Munoz et al. 2015, APJL 813, 15; Merritt et al. 2016, ApJ 833, 168). In this context, the VST survey of Early-type Galaxies in the Southern hemisphere (VEGAS) (see is producing competitive results. Starting with a small sample of six massive early-type galaxies in VEGAS, confirm the feasibility of such a survey to reach the faint surface brightness levels of 27 - 30~mag/arcsec^2 in the g band, out to about 10 R_e (Capaccioli et al. 2015, A&A 581, 10; Spavone et al. 2017 A&A, 603, 38). Therefore, taking advantage of the deep photometry, we can address the build up history of the stellar halo by comparing the surface brightness profile and the stellar mass fraction with the prediction of cosmological galaxy formation. As part of VEGAS, the Fornax Deep Survey (FDS) at VST aims to cover the Fornax cluster out to the virial radius (~0.7 Mpc), with an area of about 26 square degrees around the central galaxy NGC1399, and including the SW subgroup centred on FornaxA. FDS is a joint project based on VEGAS (P.I. E. Iodice) and the OmegaCam GTO (P.I. R. Peletier). One of the priority science goals of VEGAS and FDS is to study the faint outer regions of the massive galaxies in groups and clusters. The large mosaics obtained with the 1 square degree field-of-view pointings of OmegaCam at VST, plus the high angular resolution of 0.21 arcsec per pixel and the large integration time allow us to study, on the cluster scale, the galaxy structure from the brightest inner regions to the faint outskirts, where the stellar envelope merges into the intracluster light. The deep observations can be directly compared with the predictions from the up-to-date theories for the stellar halo formation and the relation with the galaxy environment.  Besides, the deep and multiband imaging of the VST surveys cited above allows us to derive the spatial distribution of candidate Globular Clusters (GCs) (see D'Abrusco et al. 2016, ApJL 819, 31 and Cantiello et al. 2017, A\&A in press, arXiv:1711.00750). The first results obtained for the two giant galaxies NGC1399, the cD at the center of the cluster, and NGC1316 (FornaxA, in the SW subgroup) are exciting and very promising (see the ESO photo releases at and We found that the core of the Fornax cluster is characterised by a very extended and diffuse envelope surrounding the luminous galaxy NGC1399: we map the surface brightness out to about 192 kpc from the galaxy center and down to mu_g ~ 31 mag/arcsec^2 in the g band. The deep photometry allows us to detect a faint stellar bridge in the intracluster region on the west side of NGC1399 and towards NGC1387. By analyzing the integrated colors of this feature, we argue that it could be due to the ongoing interaction between the two galaxies, where the outer envelope of NGC1387 on its east side is stripped away. Results were published by Iodice et al. 2016, ApJ, 552, 106. On the West side of the cluster core, we detect several patches of diffuse light in the intra-cluster region. These features are very faint (mu_r ~ 28 - 29 mag/arcsec^2 in the r band) and extends out to 250 kpc within the core. The most prominent one is concentrated between the three bright galaxies in the core, NGC1387, NGC1379 and NGC1381. The spatial distribution of the blue globular clusters coincides with the intra-cluster patches of light, suggesting that these regions in the core of the cluster are populated by intra-cluster material (Iodice et al. 2017, ApJ, 851, 75). A new deep mosaic of the south-west group of the Fornax cluster was obtained with VST, in the g and r bands, which covers an area of about 4 x 2 square degrees around the brightest cluster member NGC1316 (also known as FornaxA). We map the surface brightness out to ~200 kpc from the galaxy center and down to mu_g ~ 30 mag/arcsec^2. The deep VST images allows us to study with a great detail the numerous substructures that characterised this fascinating galaxy, both in the center and in the region of the stellar envelope, and reveal new faint loops and tails in the galaxy envelope (Iodice et al. 2017, ApJ, 839, 21).

contact: Stefano Borgani

Wed, SEP 5, 2018  --- TBC
SPEAKER:  Mario Gennaro (STScI, Baltimore, MD, USA)

contact: Francesca Matteucci

Wed, OCT 17, 2018 
SPEAKER: Tony Mroczkowski (ESO, Garching, DE) 
TITLE: [radio and SZ effect in clusters of galaxies]

contact: Alex Saro

Wed, OCT 24, 2018 
SPEAKER: Sarah Bosman (UCL: University College London, London, UK)
TITLE: [high redshift QSO absorptions]

contact: Valentina D'Odorico

Wed, NOV 7, 2018 
SPEAKER: Annalisa De Cia (ESO, Garching, DE)  
TITLE: [dust at high redshift?]

contact: Valentina D'Odorico

Wed, , 2018