The bright end of the galaxy luminosity function at z & SIME; 7 from the VISTA VIDEO survey

We have conducted a search for z & SIME; 7 Lyman-break galaxies over 8.2 deg(2) of near-infrared imaging from the Visible and Infrared Survey Telescope for Astronomy (VISTA) Deep Extragalactic Observations (VIDEO) survey in the XMM-Newton-Large Scale Structure (XMM-LSS) and the Extended Chandra Deep Field-South (ECDF-S) fields. Candidate galaxies were selected from a full photometric redshift analysis down to a Y + J depth of 25.3 (5 & sigma;), utilizing deep auxiliary optical and Spitzer/Infrared Array Camera (IRAC) data to remove brown dwarf and red interloper galaxy contaminants. Our final sample consists of 28 candidate galaxies at 6.5 & LE; z & LE; 7.5 with -23.5 & LE; M-UV & LE; -21.6. We derive stellar masses of 9.1 & LE; log(10)(M-?/M-& ODOT;) & LE; 10.9 for the sample, suggesting that these candidates represent some of the most massive galaxies known at this epoch. We measure the rest-frame ultraviolet (UV) luminosity function (LF) at z & SIME; 7, confirming previous findings of a gradual decline in number density at the bright end (M-UV < -22) that is well described by a double power law (DPL). We show that quasar contamination in this magnitude range is expected to be minimal, in contrast to conclusions from recent pure-parallel Hubble studies. Our results are up to a factor of 10 lower than previous determinations from optical-only ground-based studies at M-UV & LSIM; -23. We find that the inclusion of YJHK(s) photometry is vital for removing brown dwarf contaminants, and z & SIME; 7 samples based on red optical data alone could be highly contaminated (& GSIM;50 per cent). In comparison with other robust z > 5 samples, our results further support little evolution in the very bright end of the rest-frame UV LF from z = 5-10, potentially signalling a lack of mass quenching and/or dust obscuration in the most massive galaxies in the first Gyr.