Photometric Objects Around Cosmic Webs (PAC) Delineated in a Spectroscopic Survey. III. Accurate Measurement of Galaxy Stellar Mass Function with the Aid of Cosmological Redshift Surveys

TL;DR

This paper introduces a new, direct, and model-independent method to measure the galaxy stellar mass function (GSMF) across different redshifts, extending to lower masses than previous spectroscopic surveys, and provides detailed measurements for testing galaxy formation theories.

Contribution

The paper presents a novel photometric-based method to accurately measure the GSMF at lower stellar masses and higher redshifts, improving upon previous spectroscopic limitations.

Findings

No evolution of GSMF from z=0.6 to 0.1 for M*>10^{10.6} M_sun

Detection of a up-turn at M*≈10^{9.5} M_sun in local GSMF

Provided a double Schechter fit for the local GSMF

Abstract

We present a novel method to accurately measure the galaxy stellar mass function (GSMF) based upon the Photometric objects Around Cosmic webs (PAC) method developed in our first paper (Paper I) of the series. The method allows us to measure the GSMF to a lower mass end that is not accessible to the spectroscopic sample used in the PAC. Compared with Paper I, the current measurement of GSMF is direct and model independent. We measure the GSMFs in the redshift ranges of $z_s<0.2$, $0.2<z_s<0.4$ and $0.5<z_s<0.7$ down to the stellar mass $M_*=10^{8.2}$, $10^{10.6}$ and $10^{10.6}M_{\odot}$, using the data from the DESI Legacy Imaging Surveys and the spectroscopic samples of Slogan Digital Sky Survey (i.e. Main, LOWZ and CMASS samples). Our results show that there is no evolution of GSMF from $z_s=0.6$ to $z_s=0.1 $ for $M_*>10^{10.6} M_{\odot}$, and that there is a clear up-turn at $M_*\approx 10^{9.5} M_{\odot}$ towards smaller galaxies in the local GMSF at $z_s=0.1$. We provide an accurate double Schechter fit to the local GSMF for the entire range of $M_*$ and a table of our measurements at the three redshifts, which can used to test theories of galaxy formation. Our method can achieve an accurate measurement of GSMF to the stellar mass limit where the spectroscopic sample is already highly incomplete (e.g. $\sim 10^{-3}$) for its target selection.