The effect of star formation on the far-infrared-radio correlation within galaxies

E. J. Murphy, G. Helou, R. Braun, J. D.P. Kenney, L. Armus, D. Calzetti, B. T. Draine, R. C. Kennicutt, H. Roussel, F. Walter, G. J. Bendo, B. Buckalew, D. A. Dale, C. W. Engelbracht, J. D.T. Smith, M. D. Thornley

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

Using data obtained for 12 galaxies as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) and the Westerbork Synthesis Radio Telescope (WSRT) SINGS radio continuum survey, we study how star formation activity affects the far-infrared-radio correlation within galaxies by testing a phenomenological model that describes the radio image as a smeared version of the far-infrared image. The physical basis of this description is that cosmic-ray (CR) electrons will diffuse measurably farther than the mean free path of dust-heating photons before decaying by synchrotron radiation. This description works well in general. Galaxies with higher infrared surface brightnesses have best-fit smoothing scale lengths of a few hundred parsecs, substantially shorter than those for lower surface brightness galaxies. We interpret this result to suggest that galaxies with higher disk-averaged star formation rates have had a recent episode of enhanced star formation and are characterized by a higher fraction of young CR electrons that have traveled only a few hundred parsecs from their acceleration sites in supernova remnants compared to galaxies with lower star formation activity.

Original languageEnglish (US)
Pages (from-to)L111-L115
JournalAstrophysical Journal
Volume651
Issue number2 II
DOIs
StatePublished - Nov 10 2006

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Cosmic rays
  • Infrared: galaxies
  • Radio continuum: galaxies

Fingerprint Dive into the research topics of 'The effect of star formation on the far-infrared-radio correlation within galaxies'. Together they form a unique fingerprint.

  • Cite this

    Murphy, E. J., Helou, G., Braun, R., Kenney, J. D. P., Armus, L., Calzetti, D., Draine, B. T., Kennicutt, R. C., Roussel, H., Walter, F., Bendo, G. J., Buckalew, B., Dale, D. A., Engelbracht, C. W., Smith, J. D. T., & Thornley, M. D. (2006). The effect of star formation on the far-infrared-radio correlation within galaxies. Astrophysical Journal, 651(2 II), L111-L115. https://doi.org/10.1086/509722