A possible radio supernova in the outer part of NGC 3310

As part of an ongoing radio supernova monitoring program, we have discovered a variable, compact steep spectrum radio source similar to65 arcsec (similar to4 kpc) from the centre of the starburst galaxy NGC 3310. If the source is at the distance of NGC 3310, then its 5-GHz luminosity is similar to3 x 10(19) WHz(-1). The source luminosity, together with its variability characteristics, compact structure (<17 mas) and its association with a group of H II regions, leads us to propose that it is a previously uncatalogued Type II radio supernova. A search of archival data also shows an associated X-ray source with a luminosity similar to known radio supernova.