Wilson, Christine D. and Petitpas, Glen R. and Iono, Daisuke and Baker, Andrew J. and Peck, Alison B. and Krips, Melanie and Warren, Bradley and Golding, Jennifer and Atkinson, Adam and Armus, Lee and Cox, T. J. and Ho, Paul and Juvela, Mika and Matsushita, Satoki and Mihos, J. Christopher and Pihlstrom, Ylva and Yun, Min S. (2008) Luminous infrared galaxies with the submillimeter array. I. Survey overview and the central gas to dust ratio. Astrophysical Journal Supplement Series, 178 (2). pp. 189-224. ISSN 0067-0049 http://resolver.caltech.edu/CaltechAUTHORS:20090728-072507102
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We present new data obtained with the Submillimeter Array for a sample of 14 nearby luminous and ultraluminous infrared galaxies. The galaxies were selected to have distances D_L < 200 Mpc and far-infrared luminosities log L_(FIR) > 11.4. The galaxies were observed with spatial resolutions of order 1 kpc in the CO J = 3–2, CO J = 2–1,^(13)CO J = 2–1, and HCO+ J = 4–3 lines as well as the continuum at 880 μm and 1.3 mm. We have combined our CO and continuum data to measure an average gas-to-dust mass ratio of 120 ± 28 (rms deviation 109) in the central regions of these galaxies, very similar to the value of 150 determined for the Milky Way. This similarity is interesting given the more intense heating from the starburst and possibly accretion activity in the luminous infrared galaxies compared to the Milky Way. We find that the peak H_2 surface density correlates with the far-infrared luminosity, which suggests that galaxies with higher gas surface densities inside the central kiloparsec have a higher star formation rate. The lack of a significant correlation between total H_2 mass and far-infrared luminosity in our sample suggests that the increased star formation rate is due to the increased availability of molecular gas as fuel for star formation in the central regions. In contrast to previous analyses by other authors, we do not find a significant correlation between central gas surface density and the star formation efficiency, as traced by the ratio of far-infrared luminosity to nuclear gas mass. Our data show that it is the star formation rate, not the star formation efficiency, that increases with increasing central gas surface density in these galaxies.
|Additional Information:||© 2008. The American Astronomical Society. Received 2008 March 20; accepted 2008 June 7. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. The James Clerk Maxwell Telescope is operated by The Joint Astronomy Centre on behalf of the Particle Physics and Astronomy Research Council of the United Kingdom, the Netherlands Organisation for Scientific Research, and the National Research Council of Canada. This research hasmade 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. We are grateful to the many SMA observers who helped to take the data presented in this paper and to the SMATAC for giving this project a high priority. We thank James di Francesco for making available to us the pipeline processed archival SCUBA data for VV 114, NGC 5331, and Arp 299, Padelis Papadopoulos for access to his single dish CO data, and the anonymous referee for a very useful and prompt referee report. C. D.W. and J. G. acknowledge support by the Natural Science and Engineering Research Council of Canada (NSERC). A. J. B. acknowledges support by National Science Foundation grant AST 07-08653. M. J. acknowledges support by the Academy of Finland grant 124620.|
|Subject Keywords:||galaxies: individual (Arp 55, Arp 193, Arp 299, IRAS 10565+2448, IRAS 17208-0014, Mrk 231, Mrk 273, NGC 1614, NGC 2623, NGC 5331, NGC 5257, NGC 5258, NGC 6240, UGC 5101, VV 114), infrared: galaxies|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||12 Aug 2009 20:23|
|Last Modified:||26 Dec 2012 11:06|
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