The Ultraviolet and Infrared Star Formation Rates of Compact Group Galaxies: An Expanded Sample

Compact groups of galaxies provide insight into the role of low-mass, dense environments in galaxy evolution because the low velocity dispersions and close proximity of galaxy members result in frequent interactions that take place over extended time-scales. We expand the census of star formation in...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2016-07, Vol.459 (3), p.2948-2963
Main Authors: Lenkic, Laura, Tzanavaris, Panayiotis, Gallagher, Sarah C., Desjardins, Tyler D., Walker, Lisa May, Johnson, Kelsey E., Fedotov, Konstantin, Charlton, Jane, Cardiff, Ann H., Durell, Pat R.
Format: Article
Language:English
Subjects:
Astrophysics
Color
Colour
Estimates
Galactic evolution
Galaxies
Luminosity
Photometry
Star & galaxy formation
Star formation
Symbols
Ultraviolet radiation
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Summary:Compact groups of galaxies provide insight into the role of low-mass, dense environments in galaxy evolution because the low velocity dispersions and close proximity of galaxy members result in frequent interactions that take place over extended time-scales. We expand the census of star formation in compact group galaxies by Tzanavaris et al. (2010) and collaborators with Swift UVOT, Spitzer IRAC and MIPS 24 m photometry of a sample of 183 galaxies in 46 compact groups. After correcting luminosities for the contribution from old stellar populations, we estimate the dust-unobscured star formation rate (SFRUV) using the UVOT uvw2 photometry. Similarly, we use the MIPS 24 m photometry to estimate the component of the SFR that is obscured by dust (SFRIR). We find that galaxies which are MIR-active (MIR-red), also have bluer UV colours, higher specific SFRs, and tend to lie in Hi-rich groups, while galaxies that are MIR-inactive (MIR-blue) have redder UV colours, lower specific SFRs, and tend to lie in Hi-poor groups. We find the SFRs to be continuously distributed with a peak at about 1 M yr1, indicating this might be the most common value in compact groups. In contrast, the specific SFR distribution is bimodal, and there is a clear distinction between star-forming and quiescent galaxies. Overall, our results suggest that the specific SFR is the best tracer of gas depletion and galaxy evolution in compact groups.
ISSN:0035-8711
1365-8711
1365-2966
DOI:10.1093/mnras/stw779