The ultraviolet luminosity function of star-forming galaxies between redshifts of 0.4 and 0.6

We combine ultraviolet imaging of 13^H the survey field, taken with the XMM-Newton Optical Monitor telescope (XMM-OM) and the Neil Gehrels Swift Observatory Ultraviolet and Optical Telescope (UVOT) in the UVM2 band, to measure rest-frame ultraviolet 1500 Å luminosity functions of star-forming galaxies with redshifts z between 0.4 and 0.6. In total the UVM2 imaging covers a sky area of 641 arcmin², and we detect 273 galaxies in the UVM2 image with 0.4 < z < 0.6. The luminosity function is fit by a Schechter function with best-fitting values for the faint end slope α=-1.8^+0.4_-0.3 and characteristic absolute magnitude M^∗=-19.1^+0.3_-0.4. In common with XMM-OM based studies at higher redshifts, our best-fitting value for M^∗ is fainter than previous measurements. We argue that the purging of active galactic nuclei from the sample, facilitated by the cospatial X-ray survey carried out with XMM-Newton is important for the determination of M^∗. At the brightest absolute magnitudes (M₁₅₀₀<-18.5),