PhD/postdoc seminar @OATs

 
Speaker 1: Roberta Tripodi
The molecular disk and dust properties of the first QSOs

The cold ISM and dust properties are key elements to understand the assembly and nature of the first QSO at the Reionisation Epoch. In particular, the [CII] and CO lines are bright tracers of the gas content that could be detected from distant galaxies. Measurements of the line widths, profiles and velocity maps of these emission lines reveal important information on the gas kinematics. Observations of the [CII] and CO emission lines from the young quasars hosts at z>~6 at high resolution show a range of kinematic properties, including velocity gradients of ordered motion, large velocity dispersion/turbulence, gas outflows, and very compact sources with no evidence of rotation. Although the [CII] has been the main gas tracer up to now, the molecular gas component and the dust/gas ratio are still little explored. I will present results of the molecular ISM and dust in a sample of QSOs at redshift z>~6 based on CO, [CII] and continuum ALMA observations at high angular resolution. These enable us to trace both the dust and gas component in our sample’s host galaxies and to describe accurately their kinematics and the relation between their distribution and their properties.



Speaker 2: Matteo Costanzi
Cosmology with optically selected cluster catalogs

Galaxy clusters have long proven to be a valuable cosmological tool: arising from the highest peaks of the matter density field, they are a sensitive probe of the growth of structures and cosmic expansion. Current and upcoming wide-area photometric surveys --- e.g. the Dark Energy Survey (DES), the Hyper Suprime-Cam Subaru Strategic Program, the Large Synoptic Survey Telescope, Euclid --- seek to use the abundance and spatial distribution of galaxy clusters to improve constraints on the dark energy and the late-time normalization of the matter power spectrum. The main limitation for the exploitation of such a large dataset is our capability of recovering unbiased cluster mass estimates from observable mass proxies; a task especially challenging in case of optically selected clusters. In this talk I will review the work I have been carrying out in the last few years aimed at the characterization and analysis of the SDSS and DES photometric cluster catalogs, with focus on the systematics affecting optical cluster catalogs and the challenges for the exploitation of forthcoming photometric cluster surveys.
 
 The seminar will be held in hybrid form in the Library seminar room (Castello Basevi - reservation required, please book here below) and on meet.google.com/hcn-oosd-maj 
 
 

Event Information

Event Date 29-09-2021 11:30
Registered 16
Available Place 4

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