Kavli Affiliate: Eiichiro Komatsu
| First 5 Authors: Ziyang Chen, Drew Jamieson, Eiichiro Komatsu, Sownak Bose, Klaus Dolag
| Summary:
The statistics of thermal gas pressure are a new and promising probe of
cosmology and astrophysics. The large-scale cross-correlation between galaxies
and the thermal Sunyaev-Zeldovich effect gives the bias-weighted mean electron
pressure, $langle b_mathrm{h}P_erangle$. In this paper, we show that
$langle b_mathrm{h}P_erangle$ is sensitive to the amplitude of fluctuations
in matter density, for example $langle b_mathrm{h}P_eranglepropto
left(sigma_8Omega_mathrm{m}^{0.81}h^{0.67}right)^{3.14}$ at redshift
$z=0$. We find that at $z<0.5$ the observed $langle b_mathrm{h}P_erangle$ is
smaller than that predicted by the state-of-the-art hydrodynamical simulations
of galaxy formation, MillenniumTNG, by a factor of $0.93$. This can be
explained by a lower value of $sigma_8$ and $Omega_mathrm{m}$, similar to
the so-called "$S_8$ tension” seen in the gravitational lensing effect,
although the influence of astrophysics cannot be completely excluded. The
difference between Magneticum and MillenniumTNG at $z<2$ is small, indicating
that the difference in the galaxy formation models used by these simulations
has little impact on $langle b_mathrm{h}P_erangle$ at this redshift range.
At higher $z$, we find that both simulations are in a modest tension with the
existing upper bounds on $langle b_mathrm{h}P_erangle$. We also find a
significant difference between these simulations there, which we attribute to a
larger sensitivity to the galaxy formation models in the high redshift regime.
Therefore, more precise measurements of $langle b_mathrm{h}P_erangle$ at all
redshifts will provide a new test of our understanding of cosmology and galaxy
formation.
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