MOIRCS DEEP SURVEY. VIII. EVOLUTION OF STAR FORMATION ACTIVITY AS A FUNCTION OF STELLAR MASS IN GALAXIES SINCE z {approx} 3
- Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan)
- Astronomical Institute, Tohoku University, Aramaki, Aoba, Sendai 980-8578 (Japan)
- Institute of Astronomy, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan)
- Koyama Astronomical Observatory, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan)
- Service d'Astrophysique, CEA Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex (France)
We study the evolution of star formation activity of galaxies at 0.5 < z < 3.5 as a function of stellar mass, using very deep NIR data taken with the Multi-Object Infrared Camera and Spectrograph on the Subaru telescope in the GOODS-North region. The NIR imaging data reach K{approx} 23-24 Vega magnitude and they allow us to construct a nearly stellar-mass-limited sample down to {approx}10{sup 9.5-10} M{sub sun} even at z {approx} 3. We estimated star formation rates (SFRs) of the sample with two indicators, namely, the Spitzer/MIPS 24 {mu}m flux and the rest-frame 2800 A luminosity. The SFR distribution at a fixed M{sub star} shifts to higher values with increasing redshift at 0.5 < z < 3.5. More massive galaxies show stronger evolution of SFR at z {approx}> 1. We found galaxies at 2.5 < z < 3.5 show a bimodality in their SSFR distribution, which can be divided into two populations by a constant SSFR of {approx}2 Gyr{sup -1}. Galaxies in the low-SSFR group have SSFRs of {approx}0.5-1.0 Gyr{sup -1}, while the high-SSFR population shows {approx}10 Gyr{sup -1}. The cosmic SFR density (SFRD) is dominated by galaxies with M{sub star} = 10{sup 10-11} M{sub sun} at 0.5 < z < 3.5, while the contribution of massive galaxies with M{sub star} = 10{sup 11-11.5} M{sub sun} shows a strong evolution at z>1 and becomes significant at z {approx} 3, especially in the case with the SFR based on MIPS 24 {mu}m. In galaxies with M{sub star} = 10{sup 10-11.5} M{sub sun}, those with a relatively narrow range of SSFR ({approx}<1 dex) dominates the cosmic SFRD at 0.5 < z < 3.5. The SSFR of galaxies that dominate the SFRD systematically increases with redshift. At 2.5 < z < 3.5, the high-SSFR population, which is relatively small in number, dominates the SFRD. Major star formation in the universe at higher redshift seems to be associated with a more rapid growth of stellar mass of galaxies.
- OSTI ID:
- 21467211
- Journal Information:
- Astrophysical Journal, Vol. 723, Issue 1; Other Information: DOI: 10.1088/0004-637X/723/1/129; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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