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

Emission line galaxies (ELGs) are used in several ongoing and upcoming surveys as tracers of the dark matter distribution. Using a new galaxy formation model, we explore the characteristics of [O II] emitters, which dominate optical ELG selections at z ≃ 1. Model [O II] emitters at 0.5 < z < 1.5 are selected to mimic the DEEP2, VVDS, eBOSS and DESI surveys. The luminosity functions of model [O II] emitters are in reasonable agreement with observations. The selected [O II] emitters are hosted by haloes with M_halo≥10^10.3h⁻¹M_⊙, with ∼90% of them being central star-forming galaxies. The predicted mean halo occupation distributions of [O II] emitters has a shape typical of that inferred for star-forming galaxies, with the contribution from central galaxies, ⟨N⟩_{[O II],cen}, being far from the canonical step function. The ⟨N⟩_{[O II],cen} can be described as the sum of an asymmetric Gaussian for disks and a step function for spheroids, which plateaus below unity. The model [O II] emitters have a clustering bias close to unity, which is below the expectations for eBOSS and DESI ELGs. At z∼1, a comparison with observed g-band selected galaxy, which are expected to be dominated by [O II] emitters, indicates that our model produces too few [O II] emitters that are satellite galaxies. This suggests the need to revise our modelling of hot gas stripping in satellite galaxies.