Galaxy luminosity functions at redshifts 0.6-1.2 in the Chandra Deep Field South

We present the rest-frame ultraviolet (UV) galaxy luminosity function (LF) and luminosity density (LD) measurements in the far-UV (1500 angstrom) wavelength, in the redshift range z = 0.6-1.2. The UV LF is derived using XMM-Newton Optical Monitor (XMM-OM), UV (1600-4000 angstrom) observations of the Chandra Deep Field South, over an area of 396 arcmin(2). Using the deep UV imaging of the CDFS, we identified >2500 galaxies in our sample with UVW1(AB) <= 24.5 mag. This sample, along with various other catalogues containing redshift information, is used to calculate the binned representation of the galaxy UV LF in the two redshift bins 0.6 <= z < 0.8 and 0.8 <= z < 1.2, having a wide range of 1500 angstrom rest-frame UV magnitudes (Delta M-1500 similar or equal to 3), reaching similar or equal to 1-1.5 magnitudes fainter than previous studies at similar redshifts. The binned LF is described well by the Schechter function form. Using maximum-likelihood, the Schechter function is fitted to the unbinned data to obtain the best-fitting values of the the UV galaxy LF parameters. We find that characteristic magnitude M* brightens by 0.8 mag from z = 0.7 to z = 1, implying an increase in the star formation activity between these redshifts, as reported by past studies. Our estimate of the faint-end slope -1.10(-0.18)(+0.19) is on the shallower side compared with previous studies at z = 0.7, whereas a value of -1.56(-0.18)(+0.19)estimated for z = 1.0, agrees with previous results given the uncertainties.

Automated summary

We present measurements of the rest-frame ultraviolet (UV) galaxy luminosity function (LF) and luminosity density (LD) in the wavelength of far-UV (1500 angstrom) for a redshift range of z = 0.6- 1.2. Our results suggest an increase in star formation activity between redshifts z = 0.7 and z = 1. We also find that the faint-end slope at z = 0.7 is shallower compared to previous studies.