Constraining the bright-end of the UV luminosity function for z ≈ 7-9 galaxies: results from CANDELS/GOODS-South

The recent Hubble Space Telescope near-infrared imaging with the Wide-Field Camera #3 (WFC 3) of the Great Observatories Origins Deep Survey South (GOODS-S) field in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) programme covering nearly 100 arcmin(2), along with already existing Advanced Camera for Surveys optical data, makes possible the search for bright galaxy candidates at redshift z approximate to 7-9 using the Lyman break technique. We present the first analysis of z'-drop z approximate to 7 candidate galaxies in this area, finding 19 objects. We also analyse Y-drops at z approximate to 8, trebling the number of bright (H-AB < 27 mag) Y-drops from our previous work, and compare our results with those of other groups based on the same data. The bright high-redshift galaxy candidates we find serve to better constrain the bright end of the luminosity function at those redshift, and may also be more amenable to spectroscopic confirmation than the fainter ones presented in various previous work on the smaller fields (the Hubble Ultra Deep Field and the WFC 3 Early Release Science observations). We also look at the agreement with previous luminosity functions derived from WFC 3 drop-out counts, finding a generally good agreement, except for the luminosity function of Yan et al. at z approximate to 8, which is strongly ruled out.