ESA Hubble Science Release | 2015 Oct 22
[img3="MACS J0416.1–2403"]http://cdn.spacetelescope.org/archives/ ... c1523a.jpg[/img3]Observations by the NASA/ESA Hubble Space Telescope have taken advantage of gravitational lensing to reveal the largest sample of the faintest and earliest known galaxies in the Universe. Some of these galaxies formed just 600 million years after the Big Bang and are fainter than any other galaxy yet uncovered by Hubble. The team has determined, for the first time with some confidence, that these small galaxies were vital to creating the Universe that we see today.
[img3="MACS J0717.5+3745"]http://cdn.spacetelescope.org/archives/ ... c1523b.jpg[/img3][hr][/hr][c]Credits: NASA, ESA and the HST Frontier Fields team (STScI)[/c][hr][/hr]
An international team of astronomers, led by Hakim Atek of the Ecole Polytechnique Fédérale de Lausanne, Switzerland, has discovered over 250 tiny galaxies that existed only 600-900 million years after the Big Bang — one of the largest samples of dwarf galaxies yet to be discovered at these epochs. The light from these galaxies took over 12 billion years to reach the telescope, allowing the astronomers to look back in time when the universe was still very young.
Although impressive, the number of galaxies found at this early epoch is not the team’s only remarkable breakthrough, as Johan Richard from the Observatoire de Lyon, France, points out, “The faintest galaxies detected in these Hubble observations are fainter than any other yet uncovered in the deepest Hubble observations.” ...
[img3="Abell 2744"]http://cdn.spacetelescope.org/archives/ ... c1523c.jpg[/img3]
Are Ultra-faint Galaxies at z=6-8 Responsible for Cosmic Reionization?
Combined Constraints from the Hubble Frontier Fields Clusters and Parallels - Hakim Atek et al
- arXiv.org > astro-ph > arXiv:1509.06764 > 22 Sep 2015 (v1), 09 Oct 2015 (v2)
