Probing galaxy bias and intergalactic gas pressure with KiDS Galaxies-tSZ-CMB lensing cross-correlations

Ziang Yan, Ludovic van Waerbeke, Tilman Tröster, Angus H. Wright, David Alonso, Marika Asgari, Maciej Bilicki, Thomas Erben, Shiming Gu, Catherine Heymans, Hendrik Hildebrandt, Gary Hinshaw, Nick Koukoufilippas, Arun Kannawadi, Konrad Kuijken, Alexander Mead, HuanYuan Shan

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We constrain the redshift dependence of gas pressure bias〈byPe〉(bias-weighted average electron pressure), whichcharacterises the thermodynamics of intergalactic gas, through a combination of cross-correlations between galaxypositions and the thermal Sunyaev-Zeldovich (tSZ) effect, as well as galaxy positions and the gravitational lensing ofthe cosmic microwave background (CMB). The galaxy sample is from the fourth data release of the Kilo-Degree Survey(KiDS). The tSZymap and the CMB lensing map are from thePlanck2015 and 2018 data releases, respectively. Themeasurements are performed in five redshift bins withz.1. With these measurements, combining galaxy-tSZ andgalaxy-CMB lensing cross-correlations allows us to break the degeneracy between galaxy bias and gas pressure bias,and hence constrain them simultaneously. In all redshift bins, the best-fit values of〈byPe〉are at a level of∼0.3 meV/cm3and increase slightly with redshift. The galaxy bias is consistent with unity in all the redshift bins. Our results arenot sensitive to the non-linear details of the cross-correlation, which are smoothed out by thePlanckbeam. Ourmeasurements are in agreement with previous measurements as well as with theoretical predictions. We also show thatour conclusions are not changed when CMB lensing is replaced by galaxy lensing, which shows the consistency of thetwo lensing signals despite their radically different redshift ranges. This study demonstrates the feasibility of usingCMB lensing to calibrate the galaxy distribution such that the galaxy distribution can be used as a mass proxy withoutrelying on the precise knowledge of the matter distribution.
Original languageEnglish
Article numberA76
Pages (from-to)1-19
Number of pages19
JournalAstronomy and Astrophysics
Publication statusPublished - 16 Jul 2021


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