Universal conditional distribution function of [OII] luminosity of galaxies, and prediction for the [OII] luminosity function at redshift z<3
Abstract
The star-forming emission line galaxies (ELGs) with strong [OII] doublet are one of the main spectroscopic targets for the ongoing and upcoming fourth generation galaxy redshift surveys. In this work, we measure the [OII] luminosity L[OII] and the near-ultraviolet band absolute magnitude MNUV for a large sample of galaxies in the redshift range of 0.6≤ z <1.45 from the Public Data Release 2 (PDR-2) of the VIMOS Public Extragalactic Redshift Survey (VIPERS). We aim to construct the intrinsic relationship between the L[OII] and MNUV through Bayesian analysis. In particular, we develop two different methods to properly correct for the incompleteness effect and observational errors in the [OII] emission line measurement. Our results indicate that the conditional distribution of L[OII] at a given MNUV can be well described by a universal probability distribution function (PDF), which is independent of MNUV or redshift. Convolving the L[OII] conditional PDF with the NUV Luminosity function (LF) available in the literature, we make a prediction for [OII] LFs at z<3. The predicted [OII] LFs are in good agreement with the observational results from the literature. Finally, we utilize the predicted [OII] LFs to estimate the number counts of [OII] emitters for the Subaru Prime Focus Spectrograph (PFS) survey. This universal conditional PDF of L[OII] provides a novel way to optimize the source targeting strategy for [OII] emitters in future galaxy redshift surveys, and to model [OII] emitters in theories of galaxy formation.