Enhanced Star Formation of Less Massive Galaxies in a Protocluster at z = 2.5
Abstract
We investigate a correlation between star formation rate (SFR) and stellar mass for Hα emission-line galaxies (HAEs) in one of the richest protoclusters ever known at z ∼ 2.5, the USS 1558-003 protocluster. This study is based on a 9.7 hr narrowband imaging data with MOIRCS on the Subaru telescope. We are able to construct a sample in combination with additional H-band data taken with WFC3 on the Hubble Space Telescope, of 100 HAEs reaching the dust-corrected SFRs down to 3 M ⊙ yr-1 and the stellar masses down to 108.0 M ⊙. We find that while the star-forming galaxies with ≳109.3 M ⊙ are located on the universal SFR-mass main sequence (MS) irrespective of the environment, less massive star-forming galaxies with ≲109.3 M ⊙ show a significant upward scatter from the MS in this protocluster. This suggests that some less massive galaxies are in a starburst phase, although we do not know yet if this is due to environmental effects.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2016
- DOI:
- 10.3847/2041-8205/826/2/L28
- arXiv:
- arXiv:1607.04040
- Bibcode:
- 2016ApJ...826L..28H
- Keywords:
-
- galaxies: clusters: general;
- galaxies: clusters: individual: USS 1558-003;
- galaxies: evolution;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 5 pages, 3 figures, 1 table, accepted for publication in the ApJ Letters