The key goal of BoRG is to find bright galaxies during the epoch of reionization (first 700 million years after the Big Bang).

BoRG is an ongoing project, started in 2010 (Hubble Cycle 17). Until 2014, our focus has been on galaxies at z~8 (~650 million years after the Big Bang).  In Cycle 22 (2014) we have been awarded about 32 days of Hubble time (480 orbits) to carry out a new campaign during 2015 which is optimized to search for yet more distant sources at z~9-10 [~500 million years after the Big Bang).

The BoRG search for redshift z~8 candidates (galaxies at ~650 million years after the Big Bang) has been very successful: From WFC3 data covering about 350 square arcmic over 78 independent lines of sight, we identified 38 very bright z ~8 galaxies with magnitude mAB < 27 (Trenti et al. 2011, 2012; Bradley et al. 2012; Schmidt et al. 2014).

Combined with our spectroscopic follow-up campaign at Keck (Treu et al. 2012, 2013) and with legacy investigations and independent analyses, BoRG data has resulted in 16 refereed publications so far, highlighting our high science return. For a full list of the publications see our Publications page.

We identify z~8 galaxy candidates as Y-dropout sources, as illustrated by the postage stamps (3”x3”) of our best and brightest galaxy to date:


This galaxy (mAB=25.9 in F125W) is detected at S/N~20 in the J (F125W) and H (F160w) bands, has flux dropping around 1 micron and then is undetected in the V band image (F606W). The resulting photometric redshift (rightmost panel) is sharply peaked at z~8.

By combining BoRG detections with ultradeep observations, we recently published a luminosity function determination at z~8 including almost 100 galaxies (Schmidt et al. 2014):


The data show a clear evolution compared to redshift z~6 despite the modest difference in time between the two redshifts (just ~300 million years).