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M. F. Bietenholz, N. Bartel (York University), M. P. Rupen (NRAO)
We report on new VLBI observations of supernova 1986J in the spiral galaxy NGC~891, and on a comprehensive analysis of these and earlier observations from t ~4 yr after the explosion date, which we estimate to be 1983.2 ±1.1. The source is a shell or composite, and continues to show a complex morphology with large brightness modulations along the ridge and with protrusions. The supernova is moderately to strongly decelerated, with the average outer radius expanding as t\,0.71 \pm 0.11. The total flux density between 1.5 and 23~GHz decreases rapidly, with the decay currently being much more rapid than found earlier. The structure in the VLBI images changes significantly with time, showing that the evolution is not self-similar. The shell structure is best visible at the latest epoch, when the protrusions have diminished somewhat in prominence, and a new compact component has appeared. Our radio flux density measurements show a clear inversion in the integrated radio spectrum above 10~GHz, which might be related to a pulsar nebula becoming visible through the debris of the explosion. We show a movie of the expanding supernova.
The author(s) of this abstract have provided an email address for comments about the abstract: mbieten@yorku.ca
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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.