Speaker
Description
In this investigation, we leverage the combination of DESI legacy imaging surveys DR9, survey vilification (sv3), and year 1 (Y1) spectroscopic redshift data to estimate the conditional luminosity and stellar mass functions (CLFs & CSMFs) of galaxies across various halo mass bins and redshift ranges, with the help of a realistic DESI mock galaxy redshift survey (MGRS) generated from a high-resolution Jiutian simulation, and utilizing the same halo-based group finder utilized in DESI observation. (1) Through a comparison of the $r$ and $z$-band luminosity functions (LFs) and stellar mass functions (SMFs) derived using both photometric and spectroscopic data, we uncover the significant impact of photoz errors on the faint-end slope of the galaxy LFs and SMFs at low redshift. There is a clear upturn in the LFs and SMFs below $10^{9} h^{-2}\rm L_\odot$ (or $h^{-2}\rm M_\odot$), with a slope that is in nice agreement with that of halo mass function at the low mass end. (2) By leveraging both the mock galaxy and mock group samples, and correcting the aforementioned photoz systematics, we obtain a set of CLF & CSMF measurements. We find at low redshift that the faint end slope of CLFs and CSMFs below $10^{9} h^{-2}\rm L_\odot$ (or $h^{-2}\rm M_\odot$) show nice agreement with that of the subhalo mass functions. These measurements have the potential to facilitate further investigations aimed at gaining a deeper understanding of the evolution of galaxies in dark matter halos.
