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          Institute: MPI für Radioastronomie     Collection: Publikationen des MPI für Radioastronomie     Display Documents

ID: 125455.0, MPI für Radioastronomie / Publikationen des MPI für Radioastronomie
Nascent starbursts in synchrotron-deficient galaxies with hot dust
Authors:Roussel, H.; Helou, G.; Beck, R.; Condon, J. J.; Bosma, A.; Matthews, K.; Jarrett, T. H.
Date of Publication (YYYY-MM-DD):2003-08-20
Title of Journal:Astrophysical Journal
Journal Abbrev.:Astrophys. J.
Issue / Number:2
Start Page:733
End Page:759
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:Three nearby galaxies that have abnormally high infrared-to-radio continuum ratios, NGC 1377, IC 1953, and NGC 4491, are investigated with a view to understanding the physical origin of their peculiarity. We review the existing data and present new radio continuum measurements along with near-infrared integral field spectroscopy and molecular gas observations. The three galaxies have low luminosities but starburst-like infrared colors; in NGC 1377, no synchrotron emission is detected at any wavelength; in IC 1953, the observed synchrotron component is attributable to the spiral disk alone and is lacking in the central regions; and the radio spectrum of NGC 4491 is unusually flat. We also compare and contrast them with NGC 4418, a heavily extinguished galaxy that shares some attributes with them. After examining various scenarios, we conclude that these galaxies are most likely observed within a few megayears of the onset of an intense star formation episode after being quiescent for at least approximate to100 Myr. This starburst, while heating the dust, has not produced optical signatures or a normal amount of cosmic rays yet. We briefly discuss the statistics of such galaxies and what they imply for star formation surveys.
Free Keywords:galaxies : starburst, galaxies : individual (IC 1953, NGC 1377, NGC 4418, NGC 4491), infrared : galaxies, radio continuum : galaxies, supernova remnants
Comment of the Author/Creator:Date: 2003, AUG 20
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Radioastronomie
External Affiliations:CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA.; Max Planck Inst Radioastron, D-53121 Bonn, Germany.; Natl Radio Astron Observ, Charlottesville, VA 22903 USA.; Observ Marseille, F-13248 Marseille 4, France.
Identifiers:ISI:000184823400013 [ID No:1]
ISSN:0004-637X [ID No:2]
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