The UV luminosity functions of Bright z>8 Galaxies: Determination from ~0.41 deg2 of HST Observations along ~sim 300 independent sightlines

Understand

We determine the bright end of the rest-frame UV luminosity function (UVLF) at $z=8-10$ by selecting bright $z\gtrsim 8$ photometric candidates from the largest systematic compilation of HST (pure-)parallel observations to date, the Super-Brightest-of-Reionizing-Galaxies (SuperBoRG) data set.

• The data set includes $\sim300$ independent sightlines from WFC3 observations, totalling $800-1300$ arcmin$^2$ (depending on redshift).
• We identify 31 $z\gtrsim8$ candidates via colour selection and photo-$z$ analysis with observed magnitude ($24.1< H_{160} <26.6$) and $1\sigma$ range probability of $58-95\%$ of being true high-z galaxies.
• Following detailed completeness and source recovery simulations, as well as modelling of interloper contamination, we derive rest-frame UVLFs at $z=8-10$ down to $M_{UV}\simeq-23$.