Extremely Red Quasars and the Missing High-z Type 2 Population
Wide-Field Surveys and QSO Physics
Nicholas P. Ross
Fred Hamann, Nadia Zakamska, Gordon Richards, Carolin Villforth, Michael Strauss
University of Edinburgh
One of the primary goals of Chandra, XMM, and Spitzer was to unveil the population of obscured AGN at high redshift (z>2). These objects, known as Type-2 QSOs, are postulated to have the same bolometric output as unobscured Type-1 QSOs, but are attenuated by dust and gas. But Type-2 QSOs at z>1 with QSO-like luminosities are conspicuously missing, even from the largest multiwavelength surveys. This is particularly puzzling, given decades of work on Type-1 demographics which establish that the QSO luminosity density peaks at z~2.5. Either the Type-2s and Type-1s are distinct populations, requiring a major re-thinking of current models, or the luminous high-z Type-2s have somehow been missed. Here we present the spectra of ``extremely red quasars'', which have spectra from SDSS/BOSS but are photometrically selected from a new WISE 22um (W4) selection technique. We argue that this is a way forward in identifying and investigate the elusive high-z Type 2 QSO population.
high-$z$ Type-2 QSO population.


16:30 - 18:00