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SUMMARY:Photometric quasars and primordial non-Gaussianity - Boris Leisted
 t (UCL)
DTSTART:20141103T130000Z
DTEND:20141103T140000Z
UID:TALK55368@talks.cam.ac.uk
CONTACT:33215
DESCRIPTION:Quasars are highly biased tracers of the large-scale structure
  and therefore powerful probes of the initial conditions and the evolution
  of the universe. However\, current spectroscopic catalogues are relativel
 y small for studying the clustering of quasars on large-scales and over ex
 tended redshift ranges. Hence one must resort to photometric catalogues\, 
 which include large numbers of quasars identified using imaging data but s
 uffer from significant stellar contamination and systematic uncertainties.
  I will present a detailed analysis of the photometric quasars from the Sl
 oan Digital Sky Survey\, and the resulting constraints on the quasar bias 
 and primordial non-Gaussianity. The constraints on $f_{\\rm NL}$\, its spe
 ctral index\, and $g_{\\rm NL}$\, are the tightest ever obtained from a si
 ngle population of quasars or galaxies\, and are competitive with the resu
 lts obtained with WMAP\, demonstrating the potential of quasars to complem
 ent CMB experiments. These results take advantage of a novel technique\, '
 extended mode projection'\, to mitigate the complex spatially-varying syst
 ematics present in the survey in a blind and robust fashion. This work is 
 a new step towards the exploitation of data from the Dark Energy Survey\, 
 Euclid and LSST\, which will require a careful mitigation of systematics i
 n order to robustly constrain new physics.
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Room]
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