Speaker:Dr. Silvia Tommasin, TAU
Title:MID-INFRARED SPECTROSCOPY OF ACTIVE GALAXIES
Abstract:
The AGN and their circumnuclear regions are site of tremendous energy generation, from accretion onto the central supermassive black hole and from energetic starbursts in the host galaxy. These processes are often obscured by large amount of dust and the most powerful method to study the nature of the obscured sources is through infrared spectroscopic observations. A spectroscopic survey of a complete sample of Seyfert galaxies has been done by the Infrared Spectrometer (IRS) onboard Spitzer satellite. It results that Seyfert type 1 and type 2 with hidden broad emission lines (observed via optical polarimetry) have same characteristics and seem to belong to the same family of objects, while type 2 without broad polarized lines have different behaviors. Analogous works can be done to inquire the nature of other families of active galaxies. This kind of analysis, combined with emission-line strength predictions by photoionization codes, leads to a better comprehension of the processes occurring in the active galaxies and therefore to a better knowledge of galaxy classification and evolution.