The nucleus of M 82 at radio and X-ray bands : discovery of a new radio population of supernova candidates.

Detailed VLA radio maps are presented of the continuum radio emission in M82 and the X-ray emission from the HRI of the Einstein X-ray satellite. The authors have discovered more than 40 new radio sources within 300 pc of M82's nucleus. It is argued that nearly all of these sources are radio supernovae or supernova remnants and their radio luminosity distribution is derived. X-ray maps, both from reprocessed Einstein data and from EXOSAT reveal that most of the X-ray emission does not come from the radio/IR complex, but rather from the inner filamentary region seen in Hα and [O II] λ3727 photographs. Its distribution is perpendicular to the stellar distribution in M82. A discussion of the apparent correlation between radio continuum and far-infrared luminosities in "starburst" galaxies is included.