NADIA ZAKAMSKA, PRINCETON UNIVERSITY

PRINCETON ASTRONOMY COLLOQUIUM - MARCH 22, 2005

ABSTRACT

Obscured quasars from the SDSS: a multi-wavelength study

The success of unification models for Seyfert galaxies raises the question of whether these models can be extended to high luminosity Active Galactic Nuclei (AGNs). Do obscured (type II) quasars exist? If so, how many are there? Until recently, only a small number of type II quasar candidates were known. Using the spectroscopic database of the Sloan Digital Sky Survey, we selected hundreds of candidate objects by their emission line properties. We are conducting a multi-wavelength follow-up of this sample from radio wavelengths to X-rays using data from HST, Chandra, XMM, Spitzer, MMT and other telescopes. Using the multiwavelength observations of type II quasars, we study the spectral energy distributions and structure of obscured quasars, probing the unification model at high luminosities. Furthermore, an optically selected sample of type II quasars can provide an independent assessment of AGN demographics at high luminosities, supplementing X-ray and IR-selected samples.