Publication Date:
2016-07-09
Description:
We compare common star formation rate (SFR) indicators in the local Universe in the Galaxy and Mass Assembly (GAMA) equatorial fields (~160 deg 2 ), 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 (SFR UV, corr ), Hα line luminosity corrected for dust using the Balmer decrement (BD) (SFR H α, corr ), and the combination of UV and infrared (IR) emission (SFR UV + IR ). We demonstrate that SFR UV, 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 ( T dust ), but not on Hα equivalent width or Sérsic index. Due to the large scatter in the IRX versus β correlation, when compared to SFR UV + IR , the β-corrected SFR UV, corr exhibits systematic deviations as a function of IRX, BD and T dust .
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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