The Bright-end Galaxy Candidates at z ∼ 9 from 79 Independent HST Fields

We present a full data analysis of the pure-parallel Hubble Space Telescope (HST) imaging observations in the Brightest of Reionizing Galaxies Survey (BoRG[z9]) in Cycle 22. The medium-deep exposures with five HST/ WFC3IR+ UVIS filter bands from 79 independent sightlines (similar to 370 arcmin(2)) provide the least biased determination of number density for z greater than or similar to 9 bright galaxies against cosmic variance. After a strict two-step selection for candidate galaxies, including dropout color and photometric redshift analyses, and revision of previous BoRG candidates, we identify one source at z similar to 10 and two sources at z similar to 9. The z similar to 10 candidate shows evidence of line-of-sight lens magnification (mu similar to 1.5), yet it appears surprisingly luminous (M-UV similar to -22.6 +/-. 0.3 mag), making it one of the brightest candidates at z > 8 known (similar to 0.3 mag brighter than the z = 8.68 galaxy EGSY8p7, spectroscopically confirmed by Zitrin and collaborators). For z similar to 9 candidates, we include previous data points at fainter magnitudes and find that the data are well fitted by a Schechter luminosity function with alpha = -2.1(-0.3)(+0.3) (MUV)* = -21.0(-0.7)(-1.4)mg, and log phi* = -4.2(-0.9)(+0.6)Mpc-3 mag(-1), for the first time without fixing any parameters. The inferred cosmic star formation rate density is consistent with unaccelerated evolution from lower redshift.