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