发稿时间:2021-11-01浏览次数:143

USTC Astronomy Colloquium Series: 2021 Fall
Where are the 4.8% baryons in the Universe?
Yin-Zhe Ma  教授
University of KwaZulu-Natal
2021/11/2, 4:00pm , 腾讯会议号:361 476 941
报告人:
Professor Yin-Zhe Ma obtained his Bachelor degree in Physics from Nanjing University, a master degree from Institute of Theoretical Physics at Chinese Academy of Sciences (supervisor: Prof. Rong-Gen Cai), and a PhD degree in Astronomy from University of Cambridge (supervisor: Prof. George Efstathiou FRS). He conducted CITA National Fellowship at University of British Columbia Canada and a research associate at University of Manchester, and then moved to University of KwaZulu-Natal South Africa as a faculty. He chairs the NAOC-UKZN Computational Astrophysics Centre and Chinese-South African Forum of Astronomy. He also serves as an adjunct professor at the Purple Mountain Observatory China, and National Astronomical Observatory China.His research focusses on observational and theoretical cosmology aimed at understanding the fundamental laws of the Universe and uncovering the nature of dark energy and dark matter. He is currently a core-member of the Square Kilometer Array (SKA) team, the Planck science team, the Hydrogen Epoch Reionization Array (HERA), CMB Stage-4 experiment, LSST (Vera C. Rubin Observatory) and an external collaboration member with ESO's KiDS survey. He has published over 100 papers, with total citation exceeded 13000, h-index 42. He was awarded the NSFC Oversea Scholar grant.
摘要:
Previous studies of galaxy formation have shown that only 10 per cent of the cosmic baryons are in stars and galaxies, while 90 per cent of them are missing. In this talk, I will present three observational studies that coherently find significant evidences of the missing baryons. The first is the cross-correlation between the kinetic Sunyaev-Zeldovich maps from Planck with the linear reconstructed velocity field. We find significance (4.6 sigma) detection of the peculiar motion of gas on Mpc scales, for which we can reconstruct the baryon fraction. The second study is the cross-correlation between the thermal Sunyaev-Zeldovich effect with gravitational lensing map and we detect the cross-correlation for 13 sigma with RCSLenS and Planck data. The third study is to stack the pairs of luminous red galaxies and subtract the halo contribution, which leads to the detection of gas within filaments. These detections coherently brings a picture of how baryons distribute in the cosmic web. I will briefly describe how these studies can be improved with CMB-S4 observations.