The Atacama Cosmology Telescope: Modeling the Gas Thermodynamics in BOSS CMASS galaxies from Kinematic and Thermal Sunyaev-Zel’dovich Measurements

Kavli Affiliate: David N. Spergel

| First 5 Authors: Stefania Amodeo, Nicholas Battaglia, Emmanuel Schaan, Simone Ferraro, Emily Moser

| Summary:

The thermal and kinematic Sunyaev-Zel’dovich effects (tSZ, kSZ) probe the
thermodynamic properties of the circumgalactic and intracluster medium (CGM and
ICM) of galaxies, groups, and clusters, since they are proportional,
respectively, to the integrated electron pressure and momentum along the
line-of-sight. We present constraints on the gas thermodynamics of CMASS
galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS) using new
measurements of the kSZ and tSZ signals obtained in a companion paper.
Combining kSZ and tSZ measurements, we measure within our model the amplitude
of energy injection $epsilon M_star c^2$, where $M_star$ is the stellar
mass, to be $epsilon=(40pm9)times10^{-6}$, and the amplitude of the
non-thermal pressure profile to be $alpha_{rm Nth}<0.2$ (2$sigma$),
indicating that less than 20% of the total pressure within the virial radius is
due to a non-thermal component. We estimate the effects of including baryons in
the modeling of weak-lensing galaxy cross-correlation measurements using the
best fit density profile from the kSZ measurement. Our estimate reduces the
difference between the original theoretical model and the weak-lensing galaxy
cross-correlation measurements in arXiv:1611.08606 by half, but does not fully
reconcile it. Comparing the kSZ and tSZ measurements to cosmological
simulations, we find that they under predict the CGM pressure and to a lesser
extent the CGM density at larger radii. This suggests that the energy injected
via feedback models in the simulations that we compared against does not
sufficiently heat the gas at these radii. We do not find significant
disagreement at smaller radii. These measurements provide novel tests of
current and future simulations. This work demonstrates the power of joint, high
signal-to-noise kSZ and tSZ observations, upon which future cross-correlation
studies will improve.

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