A turnover in the galaxy main sequence of star formation at M{sub *} ∼ 10{sup 10}M{sub ☉} for Redshifts z < 1.3
- Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
- Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliana Mariesvej 30, DK-2100 Copenhagen (Denmark)
- California Institute of Technology, MS 105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
- UMR AIM (CEA-UP7-CNRS), CEA-Saclay, Orme des Merisiers, bât. 709, F-91191 Gif-sur-Yvette Cedex (France)
- Aix Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France)
- National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
- Research School of Astrophysics, Australian National University, Canberra, ACT 0200 (Australia)
- Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland)
- National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
The relationship between galaxy star formation rates (SFRs) and stellar masses (M {sub *}) is reexamined using a mass-selected sample of ∼62,000 star-forming galaxies at z ≤ 1.3 in the COSMOS 2 deg{sup 2} field. Using new far-infrared photometry from Herschel-PACS and SPIRE and Spitzer-MIPS 24 μm, along with derived infrared luminosities from the NRK method based on galaxies' locations in the restframe color-color diagram (NUV – r) versus (r – K), we are able to more accurately determine total SFRs for our complete sample. At all redshifts, the relationship between median SFR and M {sub *} follows a power law at low stellar masses, and flattens to nearly constant SFR at high stellar masses. We describe a new parameterization that provides the best fit to the main sequence and characterizes the low mass power-law slope, turnover mass, and overall scaling. The turnover in the main sequence occurs at a characteristic mass of about M {sub 0} ∼ 10{sup 10} M {sub ☉} at all redshifts. The low mass power-law slope ranges from 0.9-1.3 and the overall scaling rises in SFR as a function of (1 + z){sup 4.12 ± 0.10}. A broken power-law fit below and above the turnover mass gives relationships of SFR∝M{sub ∗}{sup 0.88±0.06} below the turnover mass and SFR∝M{sub ∗}{sup 0.27±0.04} above the turnover mass. Galaxies more massive than M {sub *} ≳ 10{sup 10} M {sub ☉} have a much lower average specific star formation rate (sSFR) than would be expected by simply extrapolating the traditional linear fit to the main sequence found for less massive galaxies.
- OSTI ID:
- 22882678
- Journal Information:
- Astrophysical Journal, Vol. 801, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
- Country of Publication:
- United Kingdom
- Language:
- English
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