Centaurus A (NGC 5128) is the nearest (d = 3.5 Mpc; 1 " 17 pc, Hui et al. 1993) example of a giant elliptical galaxy associated with a powerful radio source. The large-scale radio morphology consists of twin radio lobes separated by 5 degrees on the sky. The compact ( milliarcsecond) radio nucleus is variable and has a strong jet extending 4 arcminutes towards the northeast lobe. The spectacular optical appearance is that of a giant elliptical galaxy that appears enveloped in a nearly edge on, warped dust lane. There is also a series of faint optical shells. The stellar population in the dominant elliptical structure is old, whilst that of the twisted dust lane is young, sporadically punctuated by HII regions, dust and gas (Graham 1979). The overall structure of Cen A resembles that of a recent ( years, Tubbs 1980) merger, between a spiral and a large elliptical galaxy. The dust lane is the source of most (90%) of the far-infrared luminosity ( ) and is thought to be re-radiated starlight from young stars in the dusty disk (Joy et al. 1988).
In Sect. 2 we describe the observations and data analysis. Sect. 3 looks at the general FIR properties and proceeds to model the HII regions and the PDRs in the dust lane. Sect. 4 summarises the results and presents our conclusions.
© European Southern Observatory (ESO) 2000
Online publication: March 21, 2000