there is a great deal of strong evidence that the nearby radiogalaxy centaurus a (ngc 5128) harbours an active galactic nucleus at its centre. apart from the radio emission, it possesses a compact, variable hard x-ray source and infrared continuum source at its nucleus. however, the simple idea that it is merely an obscured quasar appears to be in conflict with more detailed observations. extensive study of the emission line filaments has strongly suggested that the ionizing continuum is heavily beamed in a direction away from us, and hence that centaurus a may be a bl lac. this may also explain why no broad lines have been observed in polarized light, despite the fact that the near ir continuum is polarized, suggesting that some fraction of the nuclear component is seen transmitted through the dusty regions. we propose to perform observations which will, beyond doubt, determine whether centaurus a has a broad line region. such a conclusion is clearly vital to our understanding of this object which, as the closest radiogalaxy, has been the subject of extensive study and provides an obvious target for investigation of agn unification schemes.
Instrument
SWS06
Temporal Coverage
1996-08-23T02:01:46Z/1996-08-23T05:56:42Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
