Tomographic measurement of the intergalactic gas pressure through galaxy-tSZ cross-correlations

Understand

We cross-correlate maps of the thermal Sunyaev-Zeldovich (tSZ) Compton-$y$ parameter published by Planck with the projected distribution of galaxies in a set of low-redshift tomographic bins.

• We use the nearly full-sky 2MASS Photometric Redshift and WISE $\times$ SuperCOSMOS public catalogues, covering the redshift range $z\lesssim0.4$.
• Our measurements allow us to place constraints on the redshift dependence of the mass-observable relation for tSZ cluster count analyses in terms of the so-called 'hydrostatic mass bias' parameter $1-b_{\rm H}$.
• These results can also be interpreted as measurements of the bias-weighted average gas pressure $\langle bP_e\rangle$ as a function of redshift, a quantity that can be related to the thermodynamics of gas inside haloes and used to constrain energy injection processes.