The optical counterpart of the radio source close to the Seyfert 2 nucleus of NGC 5953 = ARP 91 B

Spectroscopic and morphological observations of the nuclear region of the Seyfert 2 galaxy NGC 5953 = Arp 91 B are presented. It is shown that an extended emitting region, with features typical of a supergiant H II region, is located to the west of the nucleus within a radio structure which is emitting as a nonthermal source with spectral index α = 0.6 in the 1.4-5.0 GHz range. The nonthermal radio emission is tentatively interpreted as the result of frequent supernova blasts and the consistency of this interpretation with the optical data is discussed. Another extended emitting region, located close to the nucleus to its east, in a position symmetrically opposite to the western region, is revealed by the present spectra.