G515, Revisited. I. Stellar Populations and Evidence of Nuclear Activity in A Luminous ``E+A'' Galaxy

Type Journal Article
Names Charles T. Liu, Eric J. Hooper, Karen O'Neil, David Thompson, Marsha Wolf, Thorsten Lisker
Publication The Astrophysical Journal
Volume 658
Pages 249-257
Date March 1, 2007
URL http://adsabs.harvard.edu/abs/2007ApJ...658..249L
Library Catalog NASA ADS
Abstract We present multiwavelength observations of the very luminous ``E+A'' galaxy known as G515 (J152426.50+080908.0), including deep Ks imaging, spatially resolved Hα spectroscopy, and radio observations. The data, together with detailed spectral synthesis of the galaxy's integrated stellar population, show that G515 is a ~1 Gyr old postmerger, poststarburst galaxy. We detect no Balmer line emission in the galaxy, although there is a small amount of [N II] λλ6548, 6583 Å emission. The galaxy's H I mass has a 2 σ upper limit of 1.0×109 Msolar. IRAS detections in the 60 and 100 μm bands indicate a far-infrared luminosity of ~5.8×1010 Lsolar. A small amount (~3 mJy) of radio continuum flux, which appears to be variable, has been detected. The data suggest that G515 may have once been an ultraluminous infrared galaxy, and may harbor a weak, dust-obscured active nucleus. Based on data collected at The Arecibo Observatory, part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation (NSF); Kitt Peak National Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the NSF; The MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona; and Steward Observatory, operated by the University of Arizona.
Tags GALAXIES: EVOLUTION, GALAXIES: INTERACTIONS, galaxies: individual (G515), galaxies: nuclei, galaxies: starburst
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