A GALEX ULTRAVIOLET IMAGING SURVEY OF GALAXIES IN THE LOCAL VOLUME

Journal Article · Sat Jan 15 04:00:00 EST 2011 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/192/1/6· OSTI ID:21557048

Lee, Janice C ^[1]; Gil de Paz, Armando ^[2]; Kennicutt, Jr, Robert C; Bothwell, Matthew; Johnson, Benjamin D ^[3]; Dalcanton, Julianne ^[4]; Funes S J, Jose G ^[5]; Sakai, Shoko ^[6]; Skillman, Evan ^[7]; Tremonti, Christy ^[8]

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1. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
2. Departamento de Astrofisica, Universidad Complutense de Madrid, Madrid 28040 (Spain)
3. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom)
4. Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States)
5. Vatican Observatory, Specola Vaticana, V00120 Vatican (Italy)
6. Division of Astronomy and Astrophysics, University of California, Los Angeles, Los Angeles, CA 90095-1562 (United States)
7. Department of Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)
8. Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States)

We present results from a GALEX ultraviolet (UV) survey of a complete sample of 390 galaxies within {approx}11 Mpc of the Milky Way. The UV data are a key component of the composite Local Volume Legacy, an ultraviolet-to-infrared imaging program designed to provide an inventory of dust and star formation in nearby spiral and irregular galaxies. The ensemble data set is an especially valuable resource for studying star formation in dwarf galaxies, which comprise over 80% of the sample. We describe the GALEX survey programs that obtained the data and provide a catalog of far-UV ({approx}1500 A) and near-UV ({approx}2200 A) integrated photometry. General UV properties of the sample are briefly discussed. We compute two measures of the global star formation efficiency, the star formation rate (SFR) per unit H I gas mass, and the SFR per unit stellar mass, to illustrate the significant differences that can arise in our understanding of dwarf galaxies when the FUV is used to measure the SFR instead of H{alpha}. We find that dwarf galaxies may not be as drastically inefficient in converting gas into stars as suggested by prior H{alpha} studies. In this context, we also examine the UV properties of late-type dwarf galaxies that appear to be devoid of star formation because they were not detected in previous H{alpha} narrowband observations. Nearly all such galaxies in our sample are detected in the FUV and have FUV SFRs that fall below the limit where the H{alpha} flux is robust to Poisson fluctuations in the formation of massive stars. Otherwise, the UV colors and star formation efficiencies of H{alpha}-undetected, UV-bright dwarf irregulars appear to be relatively unremarkable with respect to those exhibited by the general population of star-forming galaxies.

• OSTI ID: 21557048
• Journal Information: Astrophysical Journal, Supplement Series, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 1 Vol. 192; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CATALOGS
DOCUMENT TYPES
DUSTS
EFFICIENCY
ELECTROMAGNETIC RADIATION
EVOLUTION
GALAXIES
MILKY WAY
RADIATIONS
STARS
ULTRAVIOLET RADIATION