The Calibration of Mid-Infrared Star Formation Rate Indicators

Calzetti, D., Kennicutt, R. C., Engelbracht, C. W., Leitherer, C., Draine, B. T., Kewley, L., Moustakas, J., Sosey, M., Dale, D. A., Gordon, K. D., Helou, G. X., Hollenbach, D. J., Armus, L., Bendo, G., Bot, C., Buckalew, B., Jarrett, T., Li, A., Meyer, M., Murphy, E. J., Prescott, M., Regan, M. W., Rieke, G. H., Roussel, H., Sheth, K., Smith, J. D. T., Thornley, M. D., & Walter, F.
2007, The Astrophysical Journal, 666, 870

With the goal of investigating the degree to which the MIR emission traces the SFR, we analyze Spitzer 8 and 24 ЮМm data of star-forming regions in a sample of 33 nearby galaxies with available HST NICMOS images in the PaЮБ (1.8756 ЮМm) 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 ЮМm emission and the 24 ЮМm emission correlate with the extinction-corrected PaЮБ 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 ЮМm emission versus number of ionizing photons, including the modest deficiency of 24 ЮМm 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 ЮМm emission as a function of the number of ionizing photons is not well reproduced by the same models. The 8 ЮМm emission is contributed, in larger measure than the 24 ЮМm 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 ЮМm emission and the other using a combination of the 24 ЮМm and HЮБ luminosities (Kennicutt and coworkers), are presented. No calibration is presented for the 8 ЮМm 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. Based on observations obtained with the Spitzer Space Telescope, which is operated by JPL, Caltech, under NASA contract 1407, and with the NASA/ESA Hubble Space Telescope at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

[ADS]

ADS Citation Query
# citations = 500
citations vs. year [year,citations]
[2007,9][2008,38][2009,58][2010,69][2011,71][2012,66][2013,60][2014,64][2015,58][2016,7]

Copyright © 2012 Karl D. Gordon All Rights Reserved