http://arxiv.org/abs/2210.11713
We propose a novel subhalo abundance matching (SHAM) model that uses the virial mass of the main progenitor of each (sub)halo $M_{\rm prog}$ as a proxy of the galaxy stellar mass $M_$ at the time of observation. This $M_{\rm prog}$ model predicts the two-point correlation functions depending on the choice of the epoch $z_{\rm prog}$ at which $M_\mathrm{prog}$ is measured. With $z_{\rm prog}$ as a fitting parameter, we apply the $M_{\rm prog}$ model to the latest observed angular correlation functions of galaxy samples at $z\simeq0.4$ with varying stellar mass thresholds from $M_{,~{\rm lim}}/(h^{-2}M_\odot)=10^{11}$ to $10^{8.6}$. The $M_{\rm prog}$ model can reproduce the observations very well over the entire scale range of $0.1\textrm{–}10~h^{-1}{\rm Mpc}$. We find that, for the samples of $10^9\leq M_{,~{\rm lim}}/(h^{-2}M_\odot)\leq10^{10.2}$, the correlation functions predicted by the widely-used $V_{\rm peak}$ model lacks amplitudes at the scale of $\lesssim1~h^{-1}{\rm Mpc}$, demonstrating the high capability of our $M_\mathrm{prog}$ model to explain observed clustering measurements. The best-fit $z_{\rm prog}$ parameter is highest ($z_{\rm prog}\simeq5$) for intermediate mass galaxies at $M_\simeq10^{9.7}~h^{-2}M_\odot$, and becomes smaller towards $z_\mathrm{prog}\simeq1$ for both lower- and higher-mass galaxies. We interpret these trends as reflecting the downsizing in the in-situ star formation in lower-mass galaxies and the larger contribution of ex-situ stellar mass growth in higher-mass galaxies.
S. Masaki, D. Kashino and Y. Lin
Mon, 24 Oct 22
30/56
Comments: 11 pages, 10 figures, submitted to MNRAS