Bright galaxies at Hubble's redshift detection frontier: Preliminary results and design from the redshift z~9-10 BoRG pure-parallel HST survey

• Published in: arXiv.org 2015-12
• Main Authors: Calvi, V, Trenti, M, Stiavelli, M, Oesch, P, Bradley, L D, Schmidt, K B, Coe, D, Brammer, G, Bernard, S, Bouwens, R J, Carrasco, D, Carollo, C M, Holwerda, B W, MacKenty, J W, Mason, C A, Shull, J M, Treu, T
• Format: Article
• Language: English
• Subjects: Dark matter; Electromagnetic wave filters; Field cameras; Galaxies; Hubble Space Telescope; Ionization; Object recognition; Observatories; Photometry; Red shift; Space telescopes; Stars & galaxies
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1512.05363

We present the first results and design from the redshift z~9-10 Brightest of the Reionizing Galaxies {\it Hubble Space Telescope} survey BoRG[z9-10], aimed at searching for intrinsically luminous unlensed galaxies during the first 700 Myr after the Big Bang. BoRG[z9-10] 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 {\lambda}=0.35{\mu}m to {\lambda}=1.7{\mu}m. We analyze the initial ~130 arcmin\(^2\) of area over 28 independent lines of sight (~25% of the total planned) to search for z>7 galaxies using a combination of Lyman break and photometric redshift selections. From an effective comoving volume of (5-25) \(times 10^5\) Mpc\(^3\) for magnitudes brighter than \(m_{AB}=26.5-24.0\) in the \(H_{160}\)-band respectively, we find five galaxy candidates at z~8.3-10 detected at high confidence (S/N>8), including a source at z~8.4 with mAB=24.5 (S/N~22), which, if confirmed, would be the brightest galaxy identified at such early times (z>8). In addition, BoRG[z9-10] data yield four galaxies with \(7.3 \lesssim z \lesssim 8\). These new Lyman break galaxies with m\(\lesssim26.5\) 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.