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Long-Term Radio Monitoring of SN 1993J

Weiler, Kurt W. and Williams, Christopher L. and Panagia, Nino and Stockdale, Christopher J. and Kelley, Matthew T. and Sramek, Richard A. and Van Dyk, Schuyler D. and Marcaide, J. M. (2007) Long-Term Radio Monitoring of SN 1993J. Astrophysical Journal, 671 (2). pp. 1959-1980. ISSN 0004-637X. doi:10.1086/523258.

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We present our extensive observations of the radio emission from supernova (SN) 1993J, in M81 (NGC 3031), made with the Very Large Array, at 90, 20, 6, 3.6, 2, 1.2, and 0.7 cm, as well as numerous measurements from other telescopes and at other wavelengths. The combined data set constitutes probably the most detailed set of measurements ever established for any SN outside of the Local Group in any wavelength range. The radio emission evolves regularly in both time and frequency, and the usual interpretation in terms of shock interaction with a circumstellar medium (CSM) formed by a pre-supernova stellar wind describes the observations rather well. However, (1) The highest frequency measurements at 85-110 GHz at early times (<40 days) are not well fitted by the parameterization which describes the centimeter wavelength measurements. (2) At midcentimeter wavelengths there is often deviation from the fitted radio light curves. (3) At a time ~3100 days after shock breakout, the decline rate of the radio emission steepens from (t^(+β)) β ~ − 0.7 to –2.7 without change in the spectral index (ν^(+α); α ~ − 0.81); however, this decline is best described not as a power-law, but as an exponential decay with an e-folding time of ~1100 days. (4) The best overall fit to all of the data is a model including both nonthermal synchrotron self-absorption (SSA) and thermal free-free absorbing (FFA) components at early times, evolving to a constant spectral index, optically thin decline rate until the break. (5) The radio and X-ray light curves display quite similar behavior and both suggest a sudden increase in the supernova progenitor mass-loss rate occurred at ~8000 yr prior to shock breakout.

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Van Dyk, Schuyler D.0000-0001-9038-9950
Additional Information:© 2007 American Astronomical Society. Print publication: Issue 2 (2007 December 20); received 2007 March 6; accepted for publication 2007 September 7. We are indebted to the VLA TAC and schedulers for permitting and arranging our numerous observations over many years and to observers who have contributed data at other radio wavelengths, sometimes unpublished. K. W. W. wishes to thank the Office of Naval Research (ONR) for the 6.1 funding supporting his research. C. J. S. is a Cottrell Scholar of Research Corporation and work on this project has been supported by the NASA Wisconsin Space Grant Consortium. N. P. is Astronomer Emeritus at the Space Telescope Science Institute (STScI ) that kindly provided research facilities and partial support for this work. J. M. M. acknowledges support from grant AYA2006-14986-C02-02. Additional information and data on radio supernovae can be found on and linked pages.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Office of Naval Research (ONR)UNSPECIFIED
Cottrell Scholar of Research CorporationUNSPECIFIED
Wisconsin Space Grant ConsortiumUNSPECIFIED
Space Telescope Science InstituteUNSPECIFIED
Ministerio de Educación y Ciencia (MICINN)AYA2006-14986-C02-02
Subject Keywords:galaxies: individual (NGC 3031, M81); radio continuum: stars; stars: mass loss; supernovae: general; supernovae: individual (SN 1993J)
Issue or Number:2
Record Number:CaltechAUTHORS:20091118-122236080
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Official Citation:Long-Term Radio Monitoring of SN 1993J Kurt W. Weiler, Christopher L. Williams, Nino Panagia, Christopher J. Stockdale, Matthew T. Kelley, Richard A. Sramek, Schuyler D. Van Dyk, and J. M. Marcaide 2007 ApJ 671 1959-1980 doi: 10.1086/523258
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16750
Deposited By: Jason Perez
Deposited On:20 Nov 2009 22:28
Last Modified:08 Nov 2021 23:29

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