Document Type

Article

Publication Date

7-10-2018

Department

Physics and Astronomy

Abstract

We present follow-up imaging of two bright (L > L∗) galaxy candidates at z ≳ 8 from the Brightest of Reionizing Galaxies (BoRG) survey with the F098M filter on the Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3). The F098M filter provides an additional constraint on the flux blueward of the spectral break, and the observations are designed to discriminate between low- and high-z photometric redshift solutions for these galaxies. Our results confirm one galaxy, BoRG-0116+1425-747, as a highly probable z ∼ 8 source, but reveal that BoRG-0116+1425-630 - previously the brightest known z > 8 candidate (m AB = 24.5) - is likely to be a z ∼ 2 interloper. As this source was substantially brighter than any other z > 8 candidate, removing it from the sample has a significant impact on the derived UV luminosity function in this epoch. We show that while previous BoRG results favored a shallow power-law decline in the bright end of the luminosity function prior to reionization, there is now no evidence for departure from a Schechter function form and therefore no evidence for a difference in galaxy formation processes before and after reionization.

DOI

10.3847/2041-8213/aacd16

ORCID

0000-0002-4884-6756

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