【12.2; Seminar】2024年粒子天体物理重点实验室系列学术报告 #56：How much our knowledge of galaxy cluster properties is affected by the way samples are selected?

时间/Time: 12月2日上午9:30/ Monday, December 2nd at 9:30 a.m.

地点/Location: 多学科楼122会议室/Meeting Room 122, Multidisciplinary Building

报告人/Speaker: Dr. Stefano Andreon (INAF-OA Brera and Shandong University)

题目/Title: How much our knowledge of galaxy cluster properties is affected by the way samples are selected?

主持人/Host: 陈勇 研究员/Dr. Yong CHEN

Tencent meeting id: 983-524-724

摘要/Abstract:

Clusters can be detected in multiple ways, thanks to their galaxies, their intracluster medium and to their baryonic+non-baryonic mass (shear). Knowledge of the scaling relations between their characteristics (mass, luminosity, richness, etc.) are informative about the physical processes shaping them, but their determination is very sensitive to uncertainties on the sample selection function and in particular requires making assumptions about the abundance and the properties of the unobservable population. In addition to these statistical issues, astrophysical challenges arise from our reliance on baryon tracers to select the sample to be studied. Weak gravitational lensing (shear) allows the selection of an unbiased sample of galaxy clusters. In this talk I introduce the subject, I present new high-quality shear, X-ray, and SZ data (and results based on them) for a small shear-selected cluster sample with the purpose of shedding light on potential biases that each selection method carries. I also sketch possible future avenues for observing with SZ and X-ray facilities, such as the Sardinia Radio Telescope, AtLAST, and the Einstein probe, larger samples drawn from ongoing Euclid & planned LSST surveys.

个人简介/Bibliography:

Stefano Andreon is first astronomer of INAF-Osservatorio Astronomico di Brera, President of Astroinformatics and Astrostatistics Commission of the International Astronomical Union, Vice-President of the International Astrostatistics Association, Director of the INAF (summer) Astrostatistics school, will soon be honorary professor at the Shandong University. He is presently deeply involved with the Euclid mission (awarded Euclid Builder status in 2023), awarded the 2024 Space Achievement Award. In 2016, awarded the status of  IAA fellow. Listed in the Italian Top Scientists and in the 2023 list of Highly Cited Researchers by Elsevier.

He discovered the galaxy cluster at the second highest redshift known, JKCS041 at z=1.803 (the most distant for over a decade), and his main interest is understanding how clusters of galaxies and galaxies in clusters evolve from an observational point of view and using Bayesian methods that he teach (so far at 15 universities spread in 7 countries). His top three most cited papers address the mass dependency and scatter of the stellar and gas fractions, the scaling between richness and mass, and the evolution of faint galaxies on the red-sequence, Earlier he was one of the first astronomers using artificial intelligence tools (neural networks, self organizing maps) for photometric redshift and object detection at the end of the 90‘s, and the lead author of Bayesian Methods for the Physical Sciences book.