CaltechAUTHORS
Published December 10, 2016 | Version Published
Journal Article Open

The Bursty Star Formation Histories of Low-mass Galaxies at 0.4 < z < 1 Revealed by Star Formation Rates Measured From Hβ and FUV

Creators

  • 1. ROR icon University of California, Santa Cruz
  • 2. ROR icon Goddard Space Flight Center
  • 3. ROR icon Space Telescope Science Institute
  • 4. ROR icon Australian National University
  • 5. ROR icon Pennsylvania State University
  • 6. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 7. ROR icon Astronomical Observatory of Rome
  • 8. ROR icon University of California, Berkeley
  • 9. ROR icon University of Michigan–Ann Arbor
  • 10. ROR icon Rutgers, The State University of New Jersey
  • 11. ROR icon Aix-Marseille University
  • 12. ROR icon Complutense University of Madrid
  • 13. ROR icon University of California, Riverside
  • 14. ROR icon Infrared Processing and Analysis Center

Abstract

We investigate the burstiness of star formation histories (SFHs) of galaxies at 0.4 < z < 1 by using the ratio of star formation rates (SFRs) measured from Hβ and FUV (1500 Å) (Hβ-to-FUV ratio). Our sample contains 164 galaxies down to stellar mass (M_*) of 10^(8.5) M_⊙ in the CANDELS GOODS-N region, where Team Keck Redshift Survey Keck/DEIMOS spectroscopy and Hubble Space Telescope/WFC3 F275W images from CANDELS and Hubble Deep UV Legacy Survey are available. When the ratio of Hβ- and FUV-derived SFRs is measured, dust extinction correction is negligible (except for very dusty galaxies) with the Calzetti attenuation curve. The Hβ-to-FUV ratio of our sample increases with M_* and SFR. The median ratio is ~0.7 at M_* ~ 10^(8.5) M_⊙ (or SFR ~ 0.5 M_⊙ yr^(−1)) and increases to ~1 at M_* ~ 10^(10) M_⊙ (or SFR ~ 10 M_⊙ yr^(−1)). At M_* < 10^(9.5) M_⊙, our median Hβ-to-FUV ratio is lower than that of local galaxies at the same M_*, implying a redshift evolution. Bursty SFH on a timescale of a few tens of megayears on galactic scales provides a plausible explanation for our results, and the importance of the burstiness increases as M_* decreases. Due to sample selection effects, our Hβ-to-FUV ratio may be an upper limit of the true value of a complete sample, which strengthens our conclusions. Other models, e.g., non-universal initial mass function or stochastic star formation on star cluster scales, are unable to plausibly explain our results.

Additional Information

© 2016. The American Astronomical Society. Received 2016 April 15; revised 2016 September 26; accepted 2016 October 2; published 2016 December 6. We thank the anonymous referee for the valuable and constructive comments, which improve this article. Y.G., S.M.F., D.C.K., G.B., and H.Y. acknowledge support from NSF Grant AST-0808133. Support for Program HST-GO-12060 and HST-AR-13891 were provided by NASA through a grant from the Space Telescope Science Institute, operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. MR acknowledges support from an appointment to the NASA Postdoctoral Program at Goddard Space Flight Center. Facilities: HST (WFC3) - , Keck (DEIMOS) - .

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Additional details

Identifiers

Eprint ID
72735
Resolver ID
CaltechAUTHORS:20161212-153959377

Related works

Describes
https://arxiv.org/abs/1604.05314 (URL)

Funding

NSF
AST-0808133
NASA
NAS5-26555
NASA Postdoctoral Program
NASA Hubble Fellowship

Dates

Created
2016-12-12
Created from EPrint's datestamp field
Updated
2021-11-11
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC)