期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 434, 期 1, 页码 209-221出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stt1011
关键词
galaxies: evolution; galaxies: formation; galaxies: general; galaxies: starburst; galaxies: star formation; galaxies: stellar content
资金
- Australian Research Council (ARC)
- Super Science Fellowship [FS100100065]
- Science and Technology Facilities Council [ST/I000976/1]
- Marie Curie Actions of the European Commission (FP7-COFUND)
- STFC (UK)
- ARC (Australia)
- AAO
- Alfred P. Sloan Foundation
- National Science Foundation
- U.S. Department of Energy
- National Aeronautics and Space Administration
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- American Museum of Natural History
- Astrophysical Institute Potsdam
- University of Basel
- University of Cambridge
- Case Western Reserve University
- University of Chicago
- Drexel University
- Fermilab
- Institute for Advanced Study
- Johns Hopkins University
- Joint Institute for Nuclear Astrophysics
- Kavli Institute for Particle Astrophysics and Cosmology
- Chinese Academy of Sciences (LAMOST)
- Los Alamos National Laboratory
- Max-Planck-Institute for Astronomy (MPIA)
- Max-Planck-Institute for Astrophysics (MPA)
- New Mexico State University
- Ohio State University
- University of Pittsburgh
- University of Portsmouth
- Princeton University
- United States Naval Observatory
- University of Washington
- STFC [ST/K003577/1, ST/J001465/1, ST/J002291/1, ST/G001987/1, ST/I001166/1, ST/I00162X/1, ST/I001212/1, ST/I003088/1, ST/I000976/1, ST/H00131X/1, ST/H004548/1, ST/H007156/1, ST/H008578/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/J002291/1, ST/H008578/1, ST/H004548/1, ST/I001166/1, ST/H007156/1, ST/J001465/1, ST/I000976/1, ST/G001987/1, ST/I001212/1, ST/K003577/1, ST/H00131X/1, ST/I00162X/1, ST/I003088/1] Funding Source: researchfish
We present evidence for stochastic star formation histories in low-mass (M-* < 10(10) M-circle dot) galaxies from observations within the Galaxy And Mass Assembly (GAMA) survey. For similar to 73 000 galaxies between 0.05 < z < 0.32, we calculate star formation rates (SFR) and specific star formation rates (SSFR = SFR/M-*) from spectroscopic H alpha measurements and apply dust corrections derived from Balmer decrements. We find a dependence of SSFR on stellar mass, such that SSFRs decrease with increasing stellar mass for star-forming galaxies, and for the full sample, SSFRs decrease as a stronger function of stellar mass. We use simple parametrizations of exponentially declining star formation histories to investigate the dependence on stellar mass of the star formation time-scale and the formation redshift. We find that parametrizations previously fit to samples of z similar to 1 galaxies cannot recover the distributions of SSFRs and stellar masses observed in the GAMA sample between 0.05 < z < 0.32. In particular, a large number of low-mass (M-* < 10(10) M-circle dot) galaxies are observed to have much higher SSFRs than can be explained by these simple models over the redshift range of 0.05 < z < 0.32, even when invoking mass-dependent staged evolution. For such a large number of galaxies to maintain low stellar masses, yet harbour such high SSFRs, requires the late onset of a weak underlying exponentially declining star formation history with stochastic bursts of star formation superimposed.
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