GAMA/H-ATLAS: common star formation rate indicators and their dependence on galaxy physical parameters

L Wang, Peder Norberg, M. L P Gunawardhana, S. Heinis, I. K. Baldry, Jonathan Bland-Hawthorn, Nathan Bourne, Sarah Brough, Michael Brown, Michelle E Cluver, Anne A Cooray, E. da Cunha, Simon P Driver, L Dunne, S Dye, S Eales, Meiert W Grootes, Benne W Holwerda, Andrew Mark Hopkins, Edo IbarR J Ivison, Cameron J Lacey, Maritza Arlene Lara-Lopez, Jonathan Loveday, Steve J Maddox, Michal J Michalowski, I. Oteo, Matthew S Owers, Cristina Carmen Popescu, Daniel James B Smith, Edward N Taylor, Richard J Tuffs, P van der Werf

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Abstract

We compare common star formation rate (SFR) indicators in the local Universe in the Galaxy and Mass Assembly (GAMA) equatorial fields (~160 deg2), using ultraviolet (UV) photometry from GALEX, far-infrared and sub-millimetre (sub-mm) photometry from Herschel Astrophysical Terahertz Large Area Survey, and Hα spectroscopy from the GAMA survey. With a high-quality sample of 745 galaxies (median redshift 〈z〉 = 0.08), we consider three SFR tracers: UV luminosity corrected for dust attenuation using the UV spectral slope β (SFRUV, corr), Hα line luminosity corrected for dust using the Balmer decrement (BD) (SFRHα, corr), and the combination of UV and infrared (IR) emission (SFRUV + IR). We demonstrate that SFRUV, corr can be reconciled with the other two tracers after applying attenuation corrections by calibrating Infrared excess (IRX; i.e. the IR to UV luminosity ratio) and attenuation in the Hα (derived from BD) against β. However, β, on its own, is very unlikely to be a reliable attenuation indicator. We find that attenuation correction factors depend on parameters such as stellar mass (M*), z and dust temperature (Tdust), but not on Hα equivalent width or Sérsic index. Due to the large scatter in the IRX versus β correlation, when compared to SFRUV + IR, the β-corrected SFRUV, corr exhibits systematic deviations as a function of IRX, BD and Tdust.

Original languageEnglish
Pages (from-to)1898-1916
Number of pages19
JournalMonthly Notices of the Royal Astronomical Society
Volume461
Issue number2
DOIs
Publication statusPublished - 11 Sep 2016

Keywords

  • Galaxies: photometry
  • Galaxies: statistics
  • Infrared: galaxies
  • Methods: statistical
  • Ultraviolet: galaxies

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