The total infrared luminosity may significantly overestimate the star formation rate of quenching and recently quenched galaxies
Abstract
The total infrared (IR) luminosity is very useful for estimating the star formation rate (SFR) of galaxies, but converting the IR luminosity into an SFR relies on assumptions that do not hold for all galaxies. We test the effectiveness of the IR luminosity as an SFR indicator by applying it to synthetic spectral energy distributions generated from three-dimensional hydrodynamical simulations of isolated disc galaxies and galaxy mergers. In general, the SFR inferred from the IR luminosity agrees well with the true instantaneous SFR of the simulated galaxies. However, for the major mergers in which a strong starburst is induced, the SFR inferred from the IR luminosity can overestimate the instantaneous SFR during the post-starburst phase by greater than two orders of magnitude. Even though the instantaneous SFR decreases rapidly after the starburst, the stars that were formed in the starburst can remain dust-obscured and thus produce significant IR luminosity. Consequently, use of the IR luminosity as an SFR indicator may cause one to conclude that post-starburst galaxies are still star forming, whereas in reality, star formation was recently quenched.
Additional Information
© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 September 4. Received 2014 September 4; in original form 2014 January 28. We thank Caitlin Casey, Mattia Fumagalli, Xavier Koenig, Barry Rothberg, Daniel Schaerer, Beverly Smith, Dan Smith, and Tomo Totani for providing useful comments on the manuscript, and we especially thank Samir Salim and the anonymous referee for their very detailed comments, which led to significant improvements to the manuscript. CCH is grateful to the Klaus Tschira Foundation for financial support and acknowledges the hospitality of the Aspen Center for Physics, which is supported by the National Science Foundation Grant No. PHY-1066293. HAS and LL acknowledge partial support from NASA grants NNX12AI55G and NNX10AD68G, and JPL RSA contract 1369566. The simulations in this paper were performed on the Odyssey cluster supported by the FAS Research Computing Group at Harvard University. This research has made use of NASA's Astrophysics Data System.Attached Files
Published - MNRAS-2014-Hayward-1598-604.pdf
Submitted - 1402.0006v3.pdf
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Additional details
- Eprint ID
- 53782
- Resolver ID
- CaltechAUTHORS:20150115-115502149
- Klaus Tschira Foundation
- PHY-1066293
- NSF
- NNX12AI55G
- NASA
- NNX10AD68G
- NASA
- RSA 1369566
- JPL
- Created
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2015-01-16Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field