Spectral energy distributions (SEDs) of the central few tens of parsec region of some of the nearest, most well studied, active galactic nuclei (AGN) are presented. These genuine AGN-core SEDs, mostly from Seyfert galaxies, are characterised by two m
ain features: an IR bump with the maximum in the 2-10 micron range, and an increasing X-ray spectrum in the 1 to ~200 keV region. These dominant features are common to Seyfert type 1 and 2 objects alike. Type 2 AGN exhibit a sharp drop shortward of 2 micron, with the optical to UV region being fully absorbed, while type 1s show instead a gentle 2 micron drop ensued by a secondary, partially-absorbed optical to UV emission bump. Assuming the bulk of optical to UV photons generated in these AGN are reprocessed by dust and re-emitted in the IR in an isotropic manner, the IR bump luminosity represents >70% of the total energy output in these objects while the high energies above 20 keV are the second energetically important contribution. Galaxies selected by their warm IR colours, i.e. presenting a relatively-flat flux distribution in the 12 to 60 micron range have often being classified as AGN. The results from these high spatial resolution SEDs question this criterion as a general rule. It is found that the intrinsic shape of the IR SED of an AGN and inferred bolometric luminosity largely depart from those derived from large aperture data. AGN luminosities can be overestimated by up to two orders of magnitude if relying on IR satellite data. We find these differences to be critical for AGN luminosities below or about 10^{44} erg/s. Above this limit, AGNs tend to dominate the light of their host galaxy regardless of the aperture size used. We tentatively mark this luminosity as a threshold to identify galaxy-light- vs AGN- dominated objects.
We present the results of H- and K-band VLT/SINFONI integral field spectroscopy of the ULIRG IRAS 19254-7245 (The Super-antennae), an interacting double galaxy system containing an embedded AGN. Deep K-band spectroscopy reveals PaAlpha arising in a w
arped disc with position angle of 330 degree and an inclination i=40-55 degree. The kinemetric parameters derived for H2 are similar to PaAlpha. Two high-ionization emission lines, [SiVI] and [AlIX], are detected and we identify as [NiII] the line observed at 1.94 micron. Diluting non-stellar continuum, which was previously detected, has decayed, and the H-band continuum emission is consistent with pure stellar emission. Based on H2 emission line ratios it is likely that at the central 1-kpc region H2 is excited by UV fluorescence in dense clouds while shock excitation is dominant further out. This scenario is supported by very low PaAlpha to H2 line ratio detected outside the nuclear region and non-thermal ortho/para ratios (~2.0 - 2.5) close to the nucleus.
