The host dark matter haloes of [O II] emitters at 0.5 < z < 1.5

Abstract

Emission line galaxies (ELGs) are used in several ongoing and upcoming\nsurveys (SDSS-IV/eBOSS, DESI) as tracers of the dark matter distribution. Using\na new galaxy formation model, we explore the characteristics of [OII] emitters,\nwhich dominate optical ELG selections at $z\\simeq 1$. Model [OII] emitters at\n$0.5<z<1.5$ are selected to mimic the DEEP2, VVDS, eBOSS and DESI surveys. The\nluminosity functions of model [OII] emitters are in reasonable agreement with\nobservations. The selected [OII] emitters are hosted by haloes with $M_{\\rm\nhalo}\\geq 10^{10.3}h^{-1}{\\rm M}_{\\odot}$, with ~90% of them being central\nstar-forming galaxies. The predicted mean halo occupation distributions of\n[OII] emitters has a shape typical of that inferred for star-forming galaxies,\nwith the contribution from central galaxies, $\\langle N\n\\rangle_{\\left[OII\\right]\\, cen}$, being far from the canonical step function.\nThe $\\langle N \\rangle_{\\left[OII\\right]\\, cen}$ can be described as the sum of\nan asymmetric Gaussian for disks and a step function for spheroids, which\nplateaus below unity. The model [OII] emitters have a clustering bias close to\nunity, which is below the expectations for eBOSS and DESI ELGs. At $z\\sim 1$, a\ncomparison with observed g-band selected galaxy, which are expected to be\ndominated by [OII] emitters, indicates that our model produces too few [OII]\nemitters that are satellite galaxies. This suggests the need to revise our\nmodelling of hot gas stripping in satellite galaxies.\n