Photometric Objects around Cosmic Webs (PAC) Delineated in a Spectroscopic Survey. I. Methods

TL;DR

This paper introduces a new method called PAC for estimating the distribution of photometric objects around spectroscopic objects in redshift surveys, enabling detailed studies of galaxy formation and evolution.

Contribution

The paper presents the PAC method, which leverages current and future surveys to analyze galaxy distributions around cosmic web structures, and demonstrates its application to real data for measuring key galaxy properties.

Findings

Accurately measured stellar-halo mass relation (SHMR)

Determined stellar mass function (SMF) across a wide mass range

Measured conditional stellar mass function (CSMF) of satellite galaxies

Abstract

We provide a method for estimating the projected density distribution $\bar{n}_2w_p(r_p)$ of photometric objects around spectroscopic objects in a redshift survey. This quantity describes the distribution of Photometric sources with certain physical properties (e.g. luminosity, mass, color etc) Around Cosmic webs (PAC) traced by the spectroscopic objects. The method can make full use of current and future deep and wide photometric surveys to explore the formation of galaxies up to medium redshift ($z_s < 2$), with the aid of cosmological redshift surveys that sample only a fairly limited species of objects (e.g. Emission Line Galaxies). As an example, we apply the PAC method to the CMASS spectroscopic and HSC-SSP PDR2 photometric samples to explore the distribution of galaxies for a wide range of stellar mass from $10^{9.0}{\rm M_\odot}$ to $10^{12.0}{\rm M_\odot}$ around massive ones at $z_s\approx 0.6$. Using the abundance matching method, we model $\bar{n}_2w_p(r_p)$ in N-body simulation using MCMC sampling, and accurately measure the stellar-halo mass relation (SHMR) and stellar mass function (SMF) for the whole mass range. We can also measure the conditional stellar mass function (CSMF) of satellites for central galaxies of different mass. The PAC method has many potential applications for studying the evolution of galaxies.