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GALEX observations of low surface brightness galaxies: UV color and star formation efficiency

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Boissier, S. and Gil de Paz, Armando and Boselli, A. and Buat, V. and Madore, B. and Chemin, L. and Balkowski, C. and Amram, P. and Carignan, C. and van Driel, W. (2008) GALEX observations of low surface brightness galaxies: UV color and star formation efficiency. Astrophysical journal, 681 (1). pp. 244-257. ISSN 0004-637X

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Official URL: http://dx.doi.org/10.1086/588580


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http://iopscience.iop.org/Publisher


Abstract

We present GALEX UV observations of a sample of low surface brightness (LSB) galaxies for which H I data are available, allowing us to estimate their star formation efficiency. We find that the UV light extends to larger radii than the optical light (some galaxies, but not all, look similar to the recently discovered XUV-disk galaxies). Using a standard calibration to convert the UV light into star formation rates, we obtain lower star formation efficiencies in LSB galaxies than in high surface brightness galaxies by about one order of magnitude. We show, however, that standard calibrations may not apply to these galaxies, as the FUV–NUV color obtained from the two GALEX bands (FUV and NUV; λ_eff = 1516 and 2267 Å, respectively) is redder than expected for star-forming galaxies. This color can be interpreted as a result of internal extinction, modified initial mass function, or star formation histories characterized by bursts followed by quiescent phases. Our analysis favors this latter hypothesis.


Item Type:Article
Additional Information:

© 2008. The American Astronomical Society. All rights reserved. We thank the referee, Stacy McGaugh, for his very constructive comments, as well as David Thilker and Ted Wyder for discussions. This research is first based on the GALEX GI program GALEXGII04-0000-0067, as well as public archival data, available at the MAST archive. This research has made use of the NASA/ IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We acknowledge the usage of the HyperLeda database (http://leda.univ-lyon1.fr). This research has made use of the GOLD Mine Database.

Uncontrolled Keywords:Tully-fisher relation; Chemo-spectrophotometric evolution; Spectral energy-distribution; Resolution rotation curves; Low-mass stars; Disk galaxies; Forming galaxies; Virgo cluster; Formation thresholds; Formation history
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:35635
Deposited On:11 Feb 2016 13:28
Last Modified:10 Dec 2018 15:05

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