A search for extended ultraviolet disk (XUV-disk) galaxies in the local universe



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Gil de Paz, Armando and otros, ... (2007) A search for extended ultraviolet disk (XUV-disk) galaxies in the local universe. Astrophysical journal supplement series, 173 (2). pp. 538-571. ISSN 0067-0049

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Official URL: http://dx.doi.org/10.1086/523853


We have initiated a search for extended ultraviolet disk (XUV-disk) galaxies in the local universe. Here we compare GALEX UV and visible-NIR images of 189 nearby (D < 40 Mpc) S0-Sm galaxies included in the GALEX Atlas of Nearby Galaxies and present the first catalog of XUV-disk galaxies. We find that XUV-disk galaxies are surprisingly common but have varied relative (UV/optical) extent and morphology. Type 1 objects (≳20% incidence) have structured, UV-bright/optically faint emission features in the outer disk, beyond the traditional star formation threshold. Type 2 XUV-disk galaxies (~10% incidence) exhibit an exceptionally large, UV-bright/optically low surface brightness (LSB) zone having blue UV-K_s outside the effective extent of the inner, older stellar population, but not reaching extreme galactocentric distance. If the activity occurring in XUV-disks is episodic, a higher fraction of present-day spirals could be influenced by such outer disk star formation. Type 1 disks are associated with spirals of all types, whereas Type 2 XUV-disks are predominantly found in late-type spirals. Type 2 XUV-disks are forming stars quickly enough to double their (currently low) stellar mass in the next Gyr (assuming a constant star formation rate). XUV-disk galaxies of both types are systematically more gas-rich than the general galaxy population. Minor external perturbation may stimulate XUV-disk incidence, at least for Type 1 objects. XUV-disks are the most actively evolving galaxies growing via inside-out disk formation in the current epoch, and may constitute a segment of the galaxy population experiencing significant, continued gas accretion from the intergalactic medium or neighboring objects.

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© 2007. The American Astronomical Society. All rights reserved. Artículo firmado por 29 autores. GALEX (Galaxy Evolution Explorer) is a NASA Small Explorer, launched in 2003 April. We gratefully acknowledge NASA’s support for construction, operation, and science analysis for the GALEX mission, developed in cooperation with the Centre National d’Etudes Spatiales of France and the Korean Ministry of Science and Technology. A. G. d. P. is financed by the MAGPOP EU Marie Curie Research Training Network and partially by the Spanish Programma Nacional de Astronomía y Astrofísica under grants AYA2003-01676 and AYA2006-02358. This research has made use of the NASA/IPAC Extragalactic Database (NED). We acknowledge the use of the HyperLeda database (http://leda.univ-lyon1.fr). The Digitized Sky Surveys were produced at the Space Telescope Science Institute under US Government grant NAG W-2166. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. Some images presented in this paper were obtained from the Multimission Archive at the Space Telescope Science Institute (MAST ). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5- 26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NAG5-7584 and by other grants and contracts. This research has made use of the NASA/ IPAC Infrared Science Archive. This publication makes use of data products from the Two Micron All Sky Survey.

Uncontrolled Keywords:H-II regions; Chemo-spectrophotometric evolution; Star-formation history; Dwarf irregular galaxies; Band surface photometry; Nearby spiral galaxies; Initial mass function; Extreme outer disk; High-velocity gas; Neutral hydrogen
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:35674
Deposited On:15 Feb 2016 14:52
Last Modified:10 Dec 2018 15:05

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