The Astrophysical Journal (Jan 2024)

The DESI One-Percent Survey: A Concise Model for the Galactic Conformity of Emission-line Galaxies

  • Hongyu Gao,
  • Y. P. Jing,
  • Kun Xu,
  • Donghai Zhao,
  • Shanquan Gui,
  • Yun Zheng,
  • Xiaolin Luo,
  • Jessica Nicole Aguilar,
  • Steven Ahlen,
  • David Brooks,
  • Todd Claybaugh,
  • Shaun Cole,
  • Axel de la Macorra,
  • Jaime E. Forero-Romero,
  • Satya Gontcho A Gontcho,
  • Mustapha Ishak,
  • Andrew Lambert,
  • Martin Landriau,
  • Marc Manera,
  • Aaron Meisner,
  • Ramon Miquel,
  • Jundan Nie,
  • Mehdi Rezaie,
  • Graziano Rossi,
  • Eusebio Sanchez,
  • Michael Schubnell,
  • Hee-Jong Seo,
  • Gregory Tarlé,
  • Benjamin Alan Weaver,
  • Zhimin Zhou

DOI
https://doi.org/10.3847/1538-4357/ad09d6
Journal volume & issue
Vol. 961, no. 1
p. 74

Abstract

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Galactic conformity is the phenomenon whereby a galaxy of a certain physical property is correlated with its neighbors of the same property, implying a possible causal relationship. The observed auto correlations of emission-line galaxies (ELGs) from the highly complete DESI One-Percent Survey exhibit a strong clustering signal on small scales, providing clear evidence for the conformity effect of ELGs. Building upon the original subhalo abundance-matching (SHAM) method developed by Gao et al., we propose a concise conformity model to improve the ELG–halo connection. In this model, the number of satellite ELGs is boosted by a factor of ∼5 in the halos whose central galaxies are ELGs. We show that the mean ELG satellite number in such central halos is still smaller than 1 and that the model does not significantly increase the overall satellite fraction. With this model, we can well recover the ELG auto correlations to the smallest scales explored with the current data (i.e., r _p > 0.03 Mpc h ^−1 in real space and at s > 0.3 Mpc h ^−1 in redshift space), while the cross correlations between luminous red galaxies and ELGs are nearly unchanged. Although our SHAM model has only eight parameters, we further verify that it can accurately describe the ELG clustering in the entire redshift range from z = 0.8 to 1.6. We therefore expect that this method can be used to generate high-quality ELG lightcone mocks for DESI.

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