Strongly Decelerated Expansion of SN 1979C
A&A 384, 408–413 (2002) Astronomy DOI: 10.1051/0004-6361:20011794 & c ESO 2002 Astrophysics Strongly decelerated expansion of SN 1979C J. M. Marcaide1,M.A.P´erez-Torres1,2,E.Ros3, A. Alberdi4,P.J.Diamond5, J. C. Guirado1,L.Lara4, S. D. Van Dyk6, and K. W. Weiler7 1 Departamento de Astronom´ıa, Universitat de Val`encia, 46100 Burjassot, Spain 2 Istituto di Radioastronomia/CNR, via P. Gobetti 101, 40129 Bologna, Italy 3 Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, 53121 Bonn, Germany 4 Instituto de Astrof´ısica de Andaluc´ıa, CSIC, Apdo. Correos 3004, 18080 Granada, Spain 5 MERLIN/VLBI National Facility, Jodrell Bank Observatory, Macclesfield, Cheshire SK11 9DL, UK 6 Infrared Processing and Analysis Center, California Institute of Technology, Mail Code 100-22, Pasadena, CA 91125, USA 7 Remote Sensing Division, Naval Research Laboratory, Code 7213, Washington, DC 20375-5320, USA Received 20 July 2001 / Accepted 11 December 2001 Abstract. We observed SN 1979C in M100 on 4 June 1999, about twenty years after explosion, with a very sensitive four-antenna VLBI array at the wavelength of λ18 cm. The distance to M100 and the expansion velocities are such that the supernova cannot be fully resolved by our Earth-wide array. Model-dependent sizes for the source have been determined and compared with previous results. We conclude that the supernova shock was initially in free expansion for 6 2 yrs and then experienced a very strong deceleration. The onset of deceleration took place a few years before the abrupt trend change in the integrated radio flux density curves.
[Show full text]