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

doi:10.1086/509722

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

Astrophysical Sciences

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62 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 language	English (US)
Pages (from-to)	L111-L115
Journal	Astrophysical Journal
Volume	651
Issue number	2 II
DOIs	https://doi.org/10.1086/509722
State	Published - Nov 10 2006

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

Cosmic rays
Infrared: galaxies
Radio continuum: galaxies

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10.1086/509722

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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

@article{4762c3693dfe454f8e18e4947a6b7ae0,

title = "The effect of star formation on the far-infrared-radio correlation within galaxies",

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.",

keywords = "Cosmic rays, Infrared: galaxies, Radio continuum: galaxies",

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

note = "Funding Information: We thank Pieter van Dokkum for stimulating discussions. We also thank the anonymous referee for useful comments. E. J. M. acknowledges support for this work provided by the Spitzer Science Center Visiting Graduate Student program. As part of the Spitzer Space Telescope Legacy Science Program, support was provided by NASA through contract 1224769 issued by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.",

year = "2006",

month = nov,

day = "10",

doi = "10.1086/509722",

language = "English (US)",

volume = "651",

pages = "L111--L115",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "IOP Publishing Ltd.",

number = "2 II",

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Murphy, EJ, Helou, G, Braun, R, Kenney, JDP, Armus, L, Calzetti, D, Draine, BT, Kennicutt, RC, Roussel, H, Walter, F, Bendo, GJ, Buckalew, B, Dale, DA, Engelbracht, CW, Smith, JDT & Thornley, MD 2006, 'The effect of star formation on the far-infrared-radio correlation within galaxies', Astrophysical Journal, vol. 651, no. 2 II, pp. L111-L115. https://doi.org/10.1086/509722

TY - JOUR

T1 - The effect of star formation on the far-infrared-radio correlation within galaxies

AU - Murphy, E. J.

AU - Helou, G.

AU - Braun, R.

AU - Kenney, J. D.P.

AU - Armus, L.

AU - Calzetti, D.

AU - Draine, B. T.

AU - Kennicutt, R. C.

AU - Roussel, H.

AU - Walter, F.

AU - Bendo, G. J.

AU - Buckalew, B.

AU - Dale, D. A.

AU - Engelbracht, C. W.

AU - Smith, J. D.T.

AU - Thornley, M. D.

N1 - Funding Information: We thank Pieter van Dokkum for stimulating discussions. We also thank the anonymous referee for useful comments. E. J. M. acknowledges support for this work provided by the Spitzer Science Center Visiting Graduate Student program. As part of the Spitzer Space Telescope Legacy Science Program, support was provided by NASA through contract 1224769 issued by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.

PY - 2006/11/10

Y1 - 2006/11/10

N2 - 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.

AB - 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.

KW - Cosmic rays

KW - Infrared: galaxies

KW - Radio continuum: galaxies

UR - http://www.scopus.com/inward/record.url?scp=33845785998&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33845785998&partnerID=8YFLogxK

U2 - 10.1086/509722

DO - 10.1086/509722

M3 - Article

AN - SCOPUS:33845785998

SN - 0004-637X

VL - 651

SP - L111-L115

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 II

ER -

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

Abstract

All Science Journal Classification (ASJC) codes

Keywords

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