COMPLEX RADIO STRUCTURE IN THE PECULIAR PAIR OF INTERACTING STARBURSTGALAXIES NGC 3395 AND NGC 3396

We have observed the peculiar pair of galaxies NGC 3395 (Sc) and NGC 3 396 (Irr) with the VLA in several configurations at four frequencies, the X (8414.9 MHz), C (4885.1 MHz), L (1464.9 MHz), and P (327.5 MHz) bands. The integrated nonthermal radio spectra of the two galaxies app ear to be similar, but their radio morphologies are very different. NG C 3396 has one weak and two strong radio peaks with relatively flat sp ectral indices for the two strong peaks, and nearly all its radio emis sion is confined within the optical image. The radio emission of NGC 3 395 is more extended and has no strong peaks. The two galaxies have a common striking feature: the radio emission is not centered on the opt ical but is much stronger in the half of each galaxy that is nearer it s companion. This contradicts models in which tidal interactions cause gas to flow into the center of the galaxy and produce starbursts only there. In NGC 3395 the tidal interaction is more likely to produce sh ocks and star formation over much of the galaxy, although radio emissi on is weaker in the northwestern part of the galaxy. There may be seve ral very weak radio spots following a distorted optical spiral arm. Al so, in NGC 3395 the diffuse radio emission extends beyond the optical image. A radio bridge is found connecting the two galaxies and followi ng the intergalactic optical emission fairly closely. We do not find a ny evidence for a compact source less-than-or-equal-to 140 pc radiatin g more than 10(27) ergs s-1 in the L band in either galaxy. The contin ued existence of these galaxies, subject to disruption by external tid al forces and internal starbursts, raises several interesting question s, and we discuss these and other implications of the observations.