Radio and optical studies of supernova 1961V in NGC 1058

Radio observations of the Sc galaxy NGC 1058 at 20 cm and 6 cm reveal two radio sources. One of the sources is coincident with supernova 1961V and has a spectral index of -0.4 + or - 0.3. This is the second (and probably the third) detection of radio emission from a supernova decades after optical maximum. The absolute luminosity of SN 1961V at 20 cm is comparable to Cas A. A second source, about 2.3 arcsec to the west, has a spectral index of -0.3 + or - 0.3 and is likely to be the remnant of a supernova that was not optically detected. Optical images of NGC 1058 show two faint H II regions associated with the radio sources. Filter photometry in several bands indicates that these two H II regions are normal with respect to the many optically brighter, albeit radio-quiet, H II regions in NGC 1058.