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Keck DEIMOS Spectroscopy of a GALEX UV-Selected Sample from the Medium Imaging Survey

Mallery, Ryan P. and Rich, R. Michael and Salim, Samir and Small, Todd and Charlot, Stéphane and Seibert, Mark and Wyder, Ted and Barlow, Tom A. and Forster, Karl and Friedman, Peter G. and Martin, D. Christopher and Morrissey, Patrick and Neff, Susan G. and Schiminovich, David and Bianchi, Luciana and Donas, José and Heckman, Timothy M. and Lee, Young-Wook and Madore, Barry F. and Milliard, Bruno and Szalay, Alex S. and Welsh, Barry Y. and Yi, Sukyoung (2007) Keck DEIMOS Spectroscopy of a GALEX UV-Selected Sample from the Medium Imaging Survey. Astrophysical Journal Supplement Series, 173 (2). pp. 471-481. ISSN 0067-0049. doi:10.1086/516638.

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We report results from a pilot program to obtain spectroscopy for objects detected in the Galaxy Evolution Explorer (GALEX) Medium Imaging Survey (MIS). Our study examines the properties of galaxies detected by GALEX fainter than the Sloan Digital Sky Survey (SDSS) spectroscopic survey. This is the first study to extend the techniques of Salim and coworkers to estimate stellar masses, star formation rates (SFRs), and the b (star formation history) parameter for star-forming galaxies out to z ~ 0.7. We obtain redshifts for 50 GALEX MIS sources reaching NUV = 23.9 (AB mag) having counterparts in the SDSS Data Release 4 (DR4). Of our sample, 43 are star-forming galaxies with z < 0.7, 3 have emission-line ratios indicative of active galactic nuclei with z < 0.7, and 4 objects with z > 1 are QSOs, 3 of which are not previously cataloged. We compare our sample to a much larger sample of ~50,000 matched GALEX/SDSS galaxies with SDSS spectroscopy; while our survey is shallow, the optical counterparts to our sources reach ~3 mag fainter in SDSS r than the SDSS spectroscopic sample. We use emission-line diagnostics for the galaxies to determine that the sample contains mostly star-forming galaxies. The galaxies in the sample populate the blue sequence in the NUV − r versus Mr color-magnitude diagram. The derived stellar masses of the galaxies range from 10^8 to 10^(11) M_⊙, and derived SFRs are between 10^(−1) and 10^2 M_⊙ yr^(−1). Our sample has SFRs, luminosities, and velocity dispersions that are similar to the samples of faint compact blue galaxies studied previously in the same redshift range by Koo and collaborators, Guzmán and collaborators, and Phillips and collaborators. However, our sample is ~2 mag fainter in surface brightness than the compact blue galaxies. We find that the star formation histories for a majority of the galaxies are consistent with a recent starburst within the last 100 Myr.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Rich, R. Michael0000-0003-0427-8387
Salim, Samir0000-0003-2342-7501
Seibert, Mark0000-0002-1143-5515
Forster, Karl0000-0001-5800-5531
Martin, D. Christopher0000-0002-8650-1644
Morrissey, Patrick0000-0001-8177-1023
Bianchi, Luciana0000-0001-7746-5461
Madore, Barry F.0000-0002-1576-1676
Additional Information:© 2007 The American Astronomical Society. Received 2006 January 25; accepted 2006 July 25. GALEX 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. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. The analysis pipeline used to reduce the DEIMOS data was developed at University of California, Berkeley, with support from NSF grant AST 00-71048. The authors thank an anonymous referee for extremely helpful comments. Facilities: GALEX, Keck:II.
Group:Space Radiation Laboratory, Space Astrophysics Laboratory
Funding AgencyGrant Number
NSFAST 00-71048
Subject Keywords:galaxies : active; galaxies : high-redshift; galaxies : starburst; ultraviolet : galaxies
Issue or Number:2
Record Number:CaltechAUTHORS:20100211-112458004
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Official Citation:Keck DEIMOS Spectroscopy of a GALEX UV-Selected Sample from the Medium Imaging Survey Ryan P. Mallery, R. Michael Rich, Samir Salim, Todd Small, Stephane Charlot, Mark Seibert, Ted Wyder, Tom A. Barlow, Karl Forster, Peter G. Friedman, D. Christopher Martin, Patrick Morrissey, Susan G. Neff, David Schiminovich, Luciana Bianchi, José Donas, Timothy M. Heckman, Young-Wook Lee, Barry F. Madore, Bruno Milliard, Alex S. Szalay, Barry Y. Welsh, and Sukyoung Yi 2007 ApJS 173 471-481 doi: 10.1086/516638
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17457
Deposited By: Tony Diaz
Deposited On:16 Feb 2010 19:25
Last Modified:08 Nov 2021 23:35

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