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The Halo Masses of Obscured and Unobscured Quasars: Clustering and Lensing

Event Details

Event Dates: 

Friday, April 4, 2014 - 12:00pm

Seminar Location: 

  • CASA Conference Room C324

Speaker Name(s): 

Michael DiPompeo

Speaker Affiliation(s): 

University of Wyoming
Seminar Type/Subject

Scientific Seminar Type: 

  • Astrophysics Lunch Seminar

Event Details & Abstract: 

Recent studies of infrared-selected AGN suggest that the reddest, most obscured objects display a higher angular clustering amplitude, and thus reside in higher-mass dark matter halos. This is a direct contradiction to the prediction of the simplest unification-by-orientation models of AGN and quasars. However, clustering measurements depend strongly on the ``mask'' that removes low-quality data and describes the sky and selection function. We find that applying a robust, conservative mask to WISE-selected quasars yields a weaker but still significant difference in the bias between obscured and unobscured quasars. These findings are consistent with results from previous Spitzer surveys, and removes any scale dependence of the bias. For obscured quasars with z ~ 1 we find that obscured quasars reside in halos only a few times more massive than the halos of unobscured sources, implying a longer lifetime for the obscured phase. I will also discuss follow-up to this measurement using the independent method of cross-correlating the quasar density with lensing of the CMB.

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