BRIGHT GALAXIES AT HUBBLE’S REDSHIFT DETECTION FRONTIER: PRELIMINARY RESULTS AND DESIGN FROM THE REDSHIFT z ∼ 9–10 BoRG PURE-PARALLEL HST SURVEY

Abstract

ABSTRACT We present the first results and design from the redshift z ∼ 9–10 Brightest of the Reionizing Galaxies Hubble Space Telescope survey BoRG[ z 9–10], aimed at searching for intrinsically luminous unlensed galaxies during the first 700 Myr after the Big Bang. BoRG[ z 9–10] is the continuation of a multi-year pure-parallel near-IR and optical imaging campaign with the Wide Field Camera 3. The ongoing survey uses five filters, optimized for detecting the most distant objects and offering continuous wavelength coverage from λ = 0.35 μ m to λ = 1.7 μ m. We analyze the initial ∼130 arcmin 2 of area over 28 independent lines of sight (∼25% of the total planned) to search for galaxies using a combination of Lyman-break and photometric redshift selections. From an effective comoving volume of (5–25) × 10 5 Mpc 3 for magnitudes brighter than in the -band respectively, we find five galaxy candidates at 8.3–10 detected at high confidence ( ), including a source at 8.4 with ( ), which, if confirmed, would be the brightest galaxy identified at such early times ( ). In addition, BoRG[ z 9–10] data yield four galaxies with . These new Lyman-break galaxies with are ideal targets for follow-up observations from ground and space-based observatories to help investigate the complex interplay between dark matter growth, galaxy assembly, and reionization.