The submillimetre and millimetre spectrum of NGC 5128

Abstract

Our observations define the millimetre and submillimetre spectrum of the central 80 arcsec of NGC 5128 and show that in the submillimetre region the spectrum displays a radical departure from what, at longer wavelengths, appears to be non-thermal synchrotron emission. The observed submillimetre excess is probably the Rayleigh-Jeans tail of thermal emission from warm dust in the dark lane, which may be heated by an extended distribution of young stars and possibly partly by the nuclear source itself.