Thermal energy census with the Sunyaev-Zel'dovich effect of DESI galaxy clusters/groups and its implication on the weak lensing power spectrum

Abstract

We carry out a thermal energy census of hot baryons at $z<1$, by cross-correlating the \emph{Planck} MILCA y-map with 0.8 million clusters/groups selected from the Yang et.al (2021) catalog. The thermal Sunyaev-Zel'dovich (tSZ) effect around these clusters/groups are reliably obtained, which enables us to make our model constraints based on one-halo (1h) and two-halo (2h) contributions, respectively. (1) The total measurement S/N of the one-halo term is 63. We constrain the $Y$-$M$ relation over the halo mass range of $10^{13}$-$10^{15}{M}_{\odot }/h$, and find $Y\propto M^{\hat{I}}\pm$ with $\hat{I}\pm =1.8$ at $z=0.14$ ($\hat{I}\pm =2.1$ at $z=0.75$). The total thermal energy of gas bound to clusters/groups increases from $0.1meV/c{\mathrm{m}}^3$ at $z=0.14$ to $0.22meV/c{\mathrm{m}}^3$ at $z=0.75$. (2) The two-halo term is used to constrain the bias-weighted electron pressure $⟨b_y{P}_e⟩$. We find that $⟨b_y{P}_e⟩$ (in unit of $meV/c{\mathrm{m}}^3$) increases from $0.24\pm 0.02$ at $z=0.14$ to $0.45\pm 0.02$ at $z=0.75$. These results lead to several implications. (i) The hot gas fraction $f_{\mathrm{gas}}$ in clusters/groups monotonically increase with halo mass, where $f_{\mathrm{gas}}$ of a $10^{14}{M}_{\odot }/h$ halo is $\sim 50\%$ ($25\%$) of the cosmic mean at $z=0.14(0.75)$. (ii) By comparing the 1h- and 2h-terms, we obtain tentative constraint on the thermal energy of unbound gas. (iii) The above results lead to significant suppression of matter and weak lensing power spectrum at small scales. These implications are important for astrophysics and cosmology, and we will further investigate them with improved data and gas modeling.

Re-analyzed with the updated DESI group catalog. Major results remain unchanged. Accepted for publication in ApJ