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A Search for Extended Ultraviolet Disk (XUV-Disk) Galaxies in the Local Universe

Thilker, David A. and Bianchi, Luciana and Meurer, Gerhardt and Gil de Paz, Armando and Boissier, Samuel and Madore, Barry F. and Boselli, Alessandro and Ferguson, Annette M. N. and Muńoz-Mateos, Juan Carlos and Madsen, Greg J. and Hameed, Salman and Overzier, Roderik A. and Forster, Karl and Friedman, Peter G. and Martin, D. Christopher and Morrissey, Patrick and Neff, Susan G. and Schiminovich, David and Seibert, Mark and Small, Todd and Wyder, Ted K. and Donas, José and Heckman, Timothy M. and Lee, Young-Wook and Milliard, Bruno and Rich, R. Michael and Szalay, Alex S. and Welsh, Barry Y. and Yi, Sukyoung K. (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. doi:10.1086/523853.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Thilker, David A.0000-0002-8528-7340
Meurer, Gerhardt0000-0002-0163-2507
Gil de Paz, Armando0000-0001-6150-2854
Boissier, Samuel0000-0002-9091-2366
Madore, Barry F.0000-0002-1576-1676
Forster, Karl0000-0001-5800-5531
Martin, D. Christopher0000-0002-8650-1644
Morrissey, Patrick0000-0001-8177-1023
Seibert, Mark0000-0002-1143-5515
Rich, R. Michael0000-0003-0427-8387
Additional Information:© 2007 American Astronomical Society. Print publication: Issue 2 (2007 December); received 2007 April 30; accepted for publication 2007 September 11. GALEX (Galaxy Evolution Explorer) is a NASA Small Explorer, launched in 2003April.We gratefully acknowledgeNASA’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 Astronomı´a y Astrofı´sica 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:// The Digitized Sky Surveys were produced at the Space Telescope Science Institute under US Government grant NAGW-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. Facilities: GALEX, CTIO:2MASS, FLWO:2MASS, Sloan, PO:1.2m, UKST
Group:Space Radiation Laboratory, Space Astrophysics Laboratory
Funding AgencyGrant Number
Alfred P. Sloan FoundationUNSPECIFIED
Participating InstitutionsUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Japanese MonbukagakushoUNSPECIFIED
Max Planck SocietyUNSPECIFIED
Higher Education Funding Council for EnglandUNSPECIFIED
Subject Keywords:galaxies: evolution; ultraviolet: galaxies
Issue or Number:2
Record Number:CaltechAUTHORS:20091203-140520449
Persistent URL:
Official Citation:A Search for Extended Ultraviolet Disk (XUV-Disk) Galaxies in the Local Universe David A. Thilker, Luciana Bianchi, Gerhardt Meurer, Armando Gil de Paz, Samuel Boissier, Barry F. Madore, Alessandro Boselli, Annette M. N. Ferguson, Juan Carlos Muńoz-Mateos, Greg J. Madsen, Salman Hameed, Roderik A. Overzier, Karl Forster, Peter G. Friedman, D. Christopher Martin, Patrick Morrissey, Susan G. Neff, David Schiminovich, Mark Seibert, Todd Small, Ted K. Wyder, José Donas, Timothy M. Heckman, Young-Wook Lee, Bruno Milliard, R. Michael Rich, Alex S. Szalay, Barry Y. Welsh, and Sukyoung K. Yi 2007 ApJS 173 538-571 doi: 10.1086/523853
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16870
Deposited On:04 Jan 2010 17:38
Last Modified:08 Nov 2021 23:30

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