Cullen, H. and Alexander, P. and Green, D. A. and Clemens, M. and Sheth , K. (2007) The unusual distribution of molecular gas and star formation in Arp 140. Monthly Notices of the Royal Astronomical Society, 374 (4). pp. 1185-1197. ISSN 0035-8711 http://resolver.caltech.edu/CaltechAUTHORS:20091112-112155209
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We investigate the atomic and molecular interstellar medium and star formation of NGC 275, the late-type spiral galaxy in Arp 140, which is interacting with NGC 274, an early-type system. The atomic gas (H I) observations reveal a tidal tail from NGC 275 which extends many optical radii beyond the interacting pair. The H I morphology implies a prograde encounter between the galaxy pair approximately ~1.5 × 10^8 yr ago. The Hα emission from NGC 275 indicates clumpy irregular star formation, clumpiness which is mirrored by the underlying mass distribution as traced by the K_s-band emission. The molecular gas distribution is striking in its anticorrelation with the H II regions. Despite the evolved nature of NGC 275's interaction and its barred potential, neither the molecular gas nor the star formation is centrally concentrated. We suggest that this structure results from stochastic star formation leading to preferential consumption of the gas in certain regions of the galaxy. In contrast to the often-assumed picture of interacting galaxies, NGC 275, which appears to be close to merger, does not display enhanced or centrally concentrated star formation. If the eventual merger is to lead to a significant burst of star formation it must be preceded by a significant conversion of atomic to molecular gas as at the current rate of star formation all the molecular gas will be exhausted by the time the merger is complete.
|Additional Information:||© 2006 The Authors. Journal compilation © 2006 RAS. Accepted 2006 October 27. Received 2006 October 25; in original form 2006 September 6. We thank the staff of the OVRO and BIMA interferometers. The JCMT is operated by The Joint Astronomy Centre on behalf of the Particle Physics and Astronomy Research Council (PPARC) of the United Kingdom, the Netherlands Organisation for Scientific Research and the National Research Council of Canada. The NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. HC acknowledges receipt of a PPARC studentship.|
|Subject Keywords:||galaxies : evolution; galaxies : individual : NGC274; galaxies : individual : NGC275; galaxies : interactions; galaxies : ISM|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||25 Nov 2009 17:03|
|Last Modified:||26 Dec 2012 11:33|
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