1997A&A...328..483K

The region surrounding the active nucleus of the barred spiral galaxy NGC 1365 is observed in the [OIII]λ5007 line and neighbouring continuum using the Faint Object Camera (FOC) aboard the Hubble Space Telescope (HST). In the continuum light numerous bright ``super star clusters'' (SSCs) are seen in the nuclear region. They tend to fall on an elongated ring around the nucleus and contribute about 20% of the total continuum flux in this wavelength regime. Without applying any extinction correction the brightest SSCs have an absolute luminosity M<sub>B</sub>=-14.1mag±0.3mag and are very compact with radii R≲3pc. Complementary ground-based spectroscopy gives an extinction estimate A<sub>B</sub>=2.5mag±0.5mag towards these regions, indicating a true luminosity M<sub>B</sub>=-16.6mag±0.6mag. The bright compact radio source NGC 1365:A is found to coincide spatially with one of the SSCs. We conclude that it is a ``radio supernova''. The HST observations resolve the inner structure of the conical outflow previously seen in the [OIII]λ5007 line in ground-based observations, and reveal a complicated structure of individual emission-line clouds, some of which gather in larger agglomerations. The total luminosity in the [OIII] line amounts to L_[OIII]≃3.7x10⁴⁰erg/s where about 40% is emitted by the clouds.