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Compact radio sources in the starburst galaxy M82 and the Sigma-D relation for supernova remnantsWe have obtained an 8.4 GHz Very Large Array (VLA) A-array map of the starburst galaxy M82 with a resolution Full Width at Half Maximum (FWHM) approximately 0.182 sec. About 50 compact radio sources in the central region of M82 were detected with a peak surface brightness approximately greater than 10(exp -17) W/Hz/sq m/sr. Comparison with previous observations shows that most sources are declining in flux. Three previously visible sources have faded into the background of our map (approximately less than 0.2 mJy/beam), while a few sources, including the second and third brightest radio sources in M82, may have increased slightly in flux over the last decade. No new radio supernova was found. The birth rate of the compact radio sources is estimated to be 0.11 + or - 0.05/yr. We attribute the population of such bright, small supernova remnants (SNRs) in M82 to the high pressure in the central region that can truncate the mass loss during a red supergiant phase or allow dense ionized clouds to be present. The compact radio sources obey a Sigma(radio surface brightness) - D(diameter) relation which is remarkably similar to that followed by supernova remnants in the Galaxy and the Magellanic Clouds and by two of the strongest known extragalactic radio supernovae: SN 1986J and SN 1979C. A least-squares fit to the SNR data gives: Sigma(sub 8.4 GHz) (W/Hz/sq m/sr) = 4.4 x 10(exp -16) D(sub pc)(exp -3.5 +/- 0.1) covering seven orders of magnitude in Sigma. Possible selection effects are discussed and a theoretical discussion of the correlation is presented.
Document ID
19950034526
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Huang, Z. P.
(Univ. of Virginia, Charlottesville, VA United States)
Thuan, T. X.
(Univ. of Virginia, Charlottesville, VA United States)
Chevalier, R. A.
(Univ. of Virginia, Charlottesville, VA United States)
Condon, J. J.
(National Radio Astronomy Observatory, Charlottesville, VA United States)
Yin, Q. F.
(National Radio Astronomy Observatory, Charlottesville, VA United States)
Date Acquired
August 16, 2013
Publication Date
March 20, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 424
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A66125
Funding Number(s)
CONTRACT_GRANT: AF-AFOSR-89-0467
CONTRACT_GRANT: NAGW-2376
Distribution Limits
Public
Copyright
Other

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