Abundance matching analysis of the emission-line galaxy sample in the extended Baryon Oscillation Spectroscopic Survey

We present the measurements of the small-scale clustering for the emission-line galaxy (ELG) sample from the extended Baryon Oscillation Spectroscopic Surv e y (eBOSS) in the Sloan Digital Sk y Surv e y IV (SDSS-IV). We use conditional abundance matching method to interpret the clustering measurements from 0.34 to 70 h( -1) Mpc . In order to account for the correlation between properties of ELGs and their environment, we add a secondary connection between star formation rate of ELGs and halo accretion rate. Three parameters are introduced to model the ELG [O II ] luminosity and to mimic the target selection of eBOSS ELGs. The parameters in our models are optimized using Markov Chain Monte Carlo (MCMC) method. We find that by conditionally matching star formation rate of galaxies and the halo accretion rate, we are able to reproduce the eBOSS ELG small-scale clustering within 1 sigma error level. Our best-fitting model shows that the eBOSS ELG sample only consists of similar to 12 per cent of all star-forming galaxies, and the satellite fraction of eBOSS ELG sample is 19.3 per cent. We show that the effect of assembly bias is similar to 20 per cent on the two-point correlation function and similar to 5 per cent on the void probability function at scale of r similar to 20 h( -1) Mpc.

Automated summary

In this study, a model is developed using conditional matching and Markov Chain Monte Carlo method to interpret the small-scale clustering of eBOSS galaxies from Sloan Digital Sky Survey IV. It is found that by matching the star formation rate of galaxies and the halo accretion rate, the eBOSS ELG small-scale clustering can be reproduced within 1 sigma error level.