Luminosity function of [OII] emission-line galaxies in the MassiveBlack-II simulation

The authors examine the luminosity function (LF) of [OII] emission-line galaxies in the high-resolution cosmological simulation MassiveBlack-II (MBII). From the spectral energy distribution of each galaxy, the authors select a sub-sample of star-forming galaxies at 0.06≤z≤3.0 using the [OII] emission line luminosity L([OII]). The authors confirm that the specific star formation rate matches that in the GAMA survey. The authors show that the [OII] LF at z=1.0 from the MBII shows a good agreement with the LFs from several surveys below L([OII])=1043.0 erg/s while the low redshifts (z≤0.3) show an excess in the prediction of bright [OII] galaxies, but still displaying a good match with observations below L([OII])=1041.6 erg/s. Based on the validity in reproducing the properties of [OII] galaxies at low redshift (z≤1), the authors forecast the evolution of the [OII] LF at high redshift (z≤3), which can be tested by upcoming surveys such as the HETDEX and DESI. The slopes of the LFs at bright and faint ends range from -3 to -2 showing minima at z=2. The slope of the bright end evolves approximately as 1/(z+1) at z=2 while the faint end evolves as ~3/(z+1) at 0.6≤z≤2. In addition, a similar analysis is applied for the evolution of [OIII] LFs, which is to be explored in the forthcoming survey WFIRST-AFTA. Finally, the authors show that the auto-correlation function of [OII] and [OIII] emitting galaxies shows a rapid evolution from z=2 to 1.