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arXiv · 1512.05363

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

V. Calvi·M. Trenti·M. Stiavelli·P. Oesch·L. D. Bradley·K. B. Schmidt·D. Coe·G. Brammer·S. Bernard·R. J. Bouwens·D. Carrasco·C. M. Carollo·B. W. Holwerda·J. W. MacKenty·C. A. Mason·J. M. Shull·T. Treu
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Abstract

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 λ=0.35μm to λ=1.7μm. 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.

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V. Calvi, M. Trenti, M. Stiavelli, P. Oesch, L. D. Bradley, K. B. Schmidt, D. Coe, G. Brammer, S. Bernard, R. J. Bouwens, D. Carrasco, C. M. Carollo, B. W. Holwerda, J. W. MacKenty, C. A. Mason, J. M. Shull, T. Treu. 2015-12-16. Bright galaxies at Hubble's redshift detection frontier: Preliminary results and design from the redshift z~9-10 BoRG pure-parallel HST survey. https://doi.org/10.3847/0004-637x%2F817%2F2%2F120

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