First massive galaxy clusters emerging from the cosmic web at z~2

Abstract:

In this talk I report upon our results on the intracluster medium (ICM) of two clusters at the time when first clusters start to emerge from the cosmic web, z~2. Results are derived from new, high resolution, deep SZ and X-ray data providing us with the measurement of the two most distant resolved pressure profiles. IDCSJ1426 cluster at z=1.75 has a core whose properties are not far from the final stage, while the remaining part of the cluster is experiencing a sizable gas, heat and entropy transfer. JKCS041 at z=1.80 is caught just after a major merger event as evidenced by its SZ-X-ray peak offset, its low central pressure, and its low Compton-Y parameter compared to its WL mass. Comparison with plausible descendents shows that its ICM will experience major changes at all radii.


Speaker: 
Stefano Andreon (INAF-OA Brera, Milan, Italy)
Place: 
KIAA Shu Qi meeting room
Time: 
Tuesday, December 3, 2024 - 1:30PM
Biography: 
Stefano Andreon is an astronomer at INAF-Osservatorio Astronomico di Brera. His research focuses on the evolution of galaxy clusters and galaxies within clusters, using observational techniques and Bayesian methods. His top-cited papers cover topics such as the mass dependency and scatter of stellar and gas fractions, the scaling of richness and mass, and the evolution of faint galaxies on the red-sequence. He discovered the galaxy cluster JKCS041 at a redshift of 1.803, the second highest known at the time. Andreon was a pioneer in applying artificial intelligence tools like neural networks and self-organizing maps for photometric redshift and object detection in the late 1990s, and later, Bayesian methods for astrophysical applications. He is the lead author of Bayesian Methods for the Physical Sciences and is currently involved with the Euclid mission, for which he was awarded Euclid Builder status in 2023 and the 2024 Space Achievement Award. He was made an IAA fellow in 2016, is listed among Italy's top scientists, and was included in Elsevier’s 2023 list of Highly Cited Researchers. Andreon is President of the Astroinformatics and Astrostatistics Commission of the International Astronomical Union, Vice-President of the International Astrostatistics Association, and chairs the IAU-IAA Astrostatistics and Astroinformatics seminar series, as well as directs the INAF summer Astrostatistics school.