Probing Galaxy Bias and Intergalactic Gas Pressure with KiDS Galaxies-tSZ-CMB Lensing Cross-correlations

by Ziang Yan (the University of British Columbia)

Friday 30 Oct 2020, 10:00 → 11:00 Asia/Shanghai

TDLI Meeting Room 202

Abstract

We make tomographic measurements of galaxy-thermal Sunyaev-Zeldovich (tSZ) effect cross-correlation and 
galaxy-Cosmic Microwave Background (CMB) lensing cross-correlation. The galaxy sample is from the 4th data release of Kilo-Degree Survey; the tSZ ymap and the CMB lensing map are from the Planck 2015 and 2018 data release respectively. We model both 
tSZ signal and galaxy number density with a linear bias model. The measurements are performed in five redshift bins within 
z<1.5. With these measurements,we constrain the redshift dependence of the “gas pressure bias”&#9001;byPe&#9002;
(the average electron pressure P_e times the gas bias b_y), and the galaxy bias b_g. Combining galaxy-tSZ and galaxy-CMB lensing cross-correlations allows us to break the degeneracy between galaxy bias and gas pressure bias, hence constrain them simultaneously. The best-fit values of&#9001;byPe&#9002; are at a level of&#8764;0.3meV/cm3 and increases with redshift. The galaxy bias is consistent with one in all the redshift bins. We demonstrate that the Cosmic Infrared Background contamination inthe tSZ map is negligible.

Biography

I'm a PhD candidate in Physics at Department of Physics and Astronomy, University of British Columbia, supervised by Prof. Gary
Hinshaw and Prof. Ludovic van Waerbeke. My research focuses on probing the Universe by cross-analysing data from different large-scale structure surveys. I'm also interested in applying cosmological hydrodynamic simulations and machine learning into cosmology.

You can also find some information on my personal Homepage: https://yanzastro.github.io/

Chair

Dr. Zhi Li

Division

Astronomy and Astrophysics