IMAGING THE NUCLEAR ENVIRONMENT OF NGC-1365 WITH THE HUBBLE-SPACE-TELESCOPE

The region surrounding the active nucleus of the barred spiral galaxy NGC 1365 is observed in the [O III] lambda 5007 line and neighbouring continuum using the Faint Object Camera (FOC) aboard the Hubble Space Telescope (HST). In the continuum light numerous bright ''super star c lusters'' (SSCs) are seen in the nuclear region. They tend to fall on an elongated ring around the nucleus and contribute about 20% of the t otal continuum flux in this wavelength regime, Without applying any ex tinction correction the brightest SSCs have an absolute luminosity M-B = -14.(m)1 +/- 0.(m)3 and are very compact with radii R less than or similar to 3 pc. Complementary ground-based spectroscopy gives an exti nction estimate Ag = 2.(m)5 +/- 0.(m)5 towards these regions, indicati ng a true luminosity M-B = -16.(m)6 +/- 0.(m)6. The bright compact rad io source NGC 1365:A is found to coincide spatially with one of the SS Cs. We conclude that it is a ''radio supernova.'' The HST observations resolve the inner structure of the conical outflow previously seen in the [O III] lambda 5007 line in groundbased observations, and reveal a complicated structure of individual emission-line clouds, some of wh ich gather in larger agglomerations. The total luminosity in the [O II I] line amounts to L-[OIII] similar or equal to 3.7 x 10(40) erg s(-1) where about 40% is emitted by the clouds.