By: Professor Vassilis Charmandaris, University of Crete, Greece

Time: Oct, 14th (Thursday) 2pm

Place: Middle Conference Room

Language: English

Abstract:

The study of Seyfert galaxies is of particular interest as they trace the build up of SMBH at the centers of galaxies and they are responsible for the most of the cosmic X-ray background at redshift z~0.8. Given the high obscuration resulting from the dust in their nuclei, a large fraction of their nuclear emission is absorbed and reemitted in the infrared. I will discuss our analysis on the properties of Seyfert galaxies based mostly on our uniformly extracted low-resolution Spitzer/IRS 5.5-35micron spectra for 103 Seyferts, that is 90% of the local 12micron IRAS Seyfert sample. We find that we are able to disentangle the AGN/starburst contribution to the mid-IR emission, and estimate the circumnuclear star formation rate using typical mid-IR tracers. We also find that the mid-IR properties of both Type 1 and Type 2 Seyferts are indistinguishable at a given luminosity range, which places constrains both on the infrared optical depth to their nuclei, as well as to the validity of the unified AGN model.