The SED of Low-Luminosity AGNs at high-spatial resolution (Juan A. Fernández Ontiveros, Max-Planck-Institut für Radioastronomie, Germany)
The importance of low-luminosity AGNs (LLAGNs) lies in the fact that they permit to explore the limits of the classical picture for these objects. At very low luminosities the broad-line region and the torus –keystones of the Unified Model for AGNs– are expected to vanish, giving way to a radiatively inefficient structure (RIAF). However, the study of LLAGNs is a complex task due to the contribution of the host galaxy, which light swamps the faint active nucleus. This is specially critical in the IR range, due to the contribution of the old stellar population and/or dust in the nuclear region. Adaptive-optics imaging in the NIR with VLT/NaCo and diffraction-limited imaging in the MIR with VLT/VISIR permit us to isolate these faint nuclei for a sample of 6 nearby LLAGNs in the Southern Hemisphere. These data were extended to the optical/UV range (HST), radio (VLA, VLBI) and X-rays (Chandra, XMM-Newton, Integral), in order to build a genuine spectral energy distribution (SED) for each AGN with a consistent spatial resolution (<0.5") across the whole spectral range. This project is a follow-up of high-spatial resolution studies of the brightest and nearest Seyfert galaxies (Reunanen et al. 2010, Prieto et al. 2010). From this high-spatial resolution dataset for the sample of LLAGNs, two major differences with respect to their bright counterparts have been discovered: 1) the big thermal IR bump seen in Seyferts and associated with the torus, smears out in LLAGN, instead a self-absorbed synchrotron emission is a fair representation of the radio-IR-optical SED, and 2) no blue bump is present, although a small "red bump" at ~1 micron is arising in some targets.
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| Cuándo |
31/01/2012 de 01:00 pm a 02:00 pm |
| Dónde | DAA Seminar Room |
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