AbstractWe discuss 2.5–45 µm spectra of the Circinus galaxy and of Cen A, obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory. The large number of detected ionic fine structure lines, observable also in visually obscured sources, provides strong constraints on the shape of the ionizing spectrum, which is found to exhibit a UV bump peaking at ~ 70 eV in the case of Circinus. Pure rotational emission of molecular hydrogen, directly probing warm molecular gas, can for the first time be detected in external galaxies.
We present mid and far-infrared energy distributions of the CfA Seyfert sample, obtained with the Infrared Space Observatory photometer (ISO-PHOT). To analyse the CfA Seyfert SEDS, we apply an inversion method: the Inverse Planckian Transform, assuming that the mid- and far-IR emission is thermal. We obtain the spectral temperature distribution of sources that reproduces the observed SEDS. We compare the parameters of the spectral components found showing that there are not differences between Seyfert 1 and Seyfert 2 as for their temperatures while the emission between 12 and 25 μm is anisotropic.
AGN Spectra as Seen by the Infrared Space Observatory: First Results
