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The Calibration of Mid-Infrared Star Formation Rate Indicators

Calzetti, D. and Kennicutt, R. C. and Engelbracht, C. W. and Leitherer, C. and Draine, B. T. and Kewley, L. and Moustakas, J. and Sosey, M. and Dale, D. A. and Gordon, K. D. and Helou, G. X. and Hollenbach, D. J. and Armus, L. and Bendo, G. and Bot, C. and Buckalew, B. and Jarrett, T. and Li, A. and Meyer, M. and Murphy, E. J. and Prescott, M. and Regan, M. W. and Rieke, G. H. and Roussel, H. and Sheth, K. and Smith, J. D. T. and Thornley, M. D. and Walter, F. (2007) The Calibration of Mid-Infrared Star Formation Rate Indicators. Astrophysical Journal, 666 (2). pp. 870-895. ISSN 0004-637X. doi:10.1086/520082.

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With the goal of investigating the degree to which the MIR emission traces the SFR, we analyze Spitzer 8 and 24 μm data of star-forming regions in a sample of 33 nearby galaxies with available HST NICMOS images in the Paα (1.8756 μm) emission line. The galaxies are drawn from the SINGS sample and cover a range of morphologies and a factor ~10 in oxygen abundance. Published data on local low-metallicity starburst galaxies and LIRGs are also included in the analysis. Both the stellar continuum-subtracted 8 μm emission and the 24 μm emission correlate with the extinction-corrected Paα line emission, although neither relationship is linear. Simple models of stellar populations and dust extinction and emission are able to reproduce the observed nonlinear trend of the 24 μm emission versus number of ionizing photons, including the modest deficiency of 24 μm emission in the low-metallicity regions, which results from a combination of decreasing dust opacity and dust temperature at low luminosities. Conversely, the trend of the 8 μm emission as a function of the number of ionizing photons is not well reproduced by the same models. The 8 μm emission is contributed, in larger measure than the 24 μm emission, by dust heated by nonionizing stellar populations, in addition to the ionizing ones, in agreement with previous findings. Two SFR calibrations, one using the 24 μm emission and the other using a combination of the 24 μm and Hα luminosities (Kennicutt and coworkers), are presented. No calibration is presented for the 8 μm emission because of its significant dependence on both metallicity and environment. The calibrations presented here should be directly applicable to systems dominated by ongoing star formation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Calzetti, D.0000-0002-5189-8004
Kennicutt, R. C.0000-0001-5448-1821
Leitherer, C.0000-0003-2685-4488
Draine, B. T.0000-0002-0846-936X
Kewley, L.0000-0001-8152-3943
Dale, D. A.0000-0002-5782-9093
Helou, G. X.0000-0003-3367-3415
Armus, L.0000-0003-3498-2973
Jarrett, T.0000-0002-4939-734X
Murphy, E. J.0000-0001-7089-7325
Rieke, G. H.0000-0003-2303-6519
Sheth, K.0000-0002-5496-4118
Smith, J. D. T.0000-0003-1545-5078
Walter, F.0000-0003-4793-7880
Additional Information:© 2007 The American Astronomical Society. Received 2007 May 1; accepted 2007 May 22. The authors would like to acknowledge the anonymous referee for the speedy report and for the many constructive comments that have helped improve the manuscript. This work has been partially supported by the NASA HST grant GO-9360 and by the JPL, Caltech, contract 1224667. It is part of SINGS, The Spitzer Infrared Nearby Galaxies Survey, one of the Spitzer Space Telescope Legacy Science Programs. This work 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.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:galaxies : interactions; galaxies : ISM; galaxies : starburst; ISM : structure
Issue or Number:2
Record Number:CaltechAUTHORS:20091028-075614201
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Official Citation:The Calibration of Mid-Infrared Star Formation Rate Indicators D. Calzetti, R. C. Kennicutt, C. W. Engelbracht, C. Leitherer, B. T. Draine, L. Kewley, J. Moustakas, M. Sosey, D. A. Dale, K. D. Gordon, G. X. Helou, D. J. Hollenbach, L. Armus, G. Bendo, C. Bot, B. Buckalew, T. Jarrett, A. Li, M. Meyer, E. J. Murphy, M. Prescott, M. W. Regan, G. H. Rieke, H. Roussel, K. Sheth, J. D. T. Smith, M. D. Thornley, and F. Walter 2007 ApJ 666 870-895 doi: 10.1086/520082
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16504
Deposited By: Tony Diaz
Deposited On:02 Nov 2009 17:46
Last Modified:08 Nov 2021 23:27

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