Published online by Cambridge University Press: 04 August 2017
Large numbers (∼30) of supernova remnant candidates have been revealed in new VLA maps of the inner 600 pc of M82 with subarcsecond resolution. The flux density decrease of the bright source 41.9+58 in the M82 nuclear region is found to be occurring with an approximately constant spectral index of −0.9 at ν≳3 GHz, and the low frequency turnover has moved from ∼700 MHz in 1974–1975 to <400 MHz in 1979–81.
A model of 41.9+58 is proposed in which it is, at least initially confined by its own hot (∼108K) pre-SN ejecta, and its relativistic particles are accelerated by a pulsar at its centre.