Extreme Emission-line Galaxies in CANDELS: Broadband-selected, Starbursting Dwarf Galaxies at z > 1
Abstract
We identify an abundant population of extreme emission-line galaxies (EELGs) at redshift z ~ 1.7 in the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey imaging from Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3). Sixty-nine EELG candidates are selected by the large contribution of exceptionally bright emission lines to their near-infrared broadband magnitudes. Supported by spectroscopic confirmation of strong [O III] emission lines—with rest-frame equivalent widths ~1000 Å—in the four candidates that have HST/WFC3 grism observations, we conclude that these objects are galaxies with ~108 M ⊙ in stellar mass, undergoing an enormous starburst phase with M_*/\dot{M}_* of only ~15 Myr. These bursts may cause outflows that are strong enough to produce cored dark matter profiles in low-mass galaxies. The individual star formation rates and the comoving number density (3.7 × 10-4 Mpc-3) can produce in ~4 Gyr much of the stellar mass density that is presently contained in 108-109 M ⊙ dwarf galaxies. Therefore, our observations provide a strong indication that many or even most of the stars in present-day dwarf galaxies formed in strong, short-lived bursts, mostly at z > 1.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2011
- DOI:
- 10.1088/0004-637X/742/2/111
- arXiv:
- arXiv:1107.5256
- Bibcode:
- 2011ApJ...742..111V
- Keywords:
-
- galaxies: dwarf;
- galaxies: evolution;
- galaxies: formation;
- galaxies: high-redshift;
- galaxies: starburst;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- accepted for publication in ApJ