Ultraviolet number counts of galaxies from swift ultraviolet/optical telescope deep imaging of the chandra deep field south

Abstract

Deep Swift UV/Optical Telescope (UVOT) imaging of the Chandra Deep Field South is used to measure galaxy number counts in three near-ultraviolet (NUV) filters (uvw2: 1928 Ap̊, uvm2: 2246, and uvw1: 2600) and the u band (3645 Å). UVOT observations cover the break in the slope of the NUV number counts with greater precision than the number counts by the Hubble Space Telescope Space Telescope Imaging Spectrograph and the Galaxy Evolution Explorer, spanning a range 21 ≲ mAB ≲ 25. Model number counts confirm earlier investigations in favoring models with an evolving galaxy luminosity function. © 2009. The American Astronomical Society. All rights reserved.