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SUMMARY:Polarization tests of large scale CMB temperature anomalies - a la
 st stand before Planck - Hiranya Peiris (IoA)
DTSTART:20090427T120000Z
DTEND:20090427T130000Z
UID:TALK17463@talks.cam.ac.uk
CONTACT:Antony Lewis
DESCRIPTION:Anomalies in the large-scale CMB temperature sky measured by W
 MAP have been suggested as possible evidence for a violation of statistica
 l isotropy. In any physical model for broken isotropy\, there are testable
  consequences for the CMB polarization field. I will discuss the predictio
 ns for the polarization field in models that break statistical isotropy lo
 cally through a modulation field. I will consider two different models: di
 polar modulation\, invoked to explain the asymmetry in power between the n
 orthern and southern ecliptic hemispheres\, and quadrupolar modulation\, p
 roposed to explain the alignments between the quadrupole and octopole. I w
 ill show that the addition of polarization information substantially impro
 ves the ability to test for modulation models and to discriminate among po
 ssible explanations. Finally\, I will briefly discuss a polarization test 
 of a possible anomaly at multipoles \\ell ~ 20-40 in the observed temperat
 ure angular power spectrum\, which utilises fortuitous properties of the p
 olarization transfer function at these scales. As predictions of anomaly m
 odels\, polarization statistics move beyond the a posteriori inferences th
 at currently dominate the field.
LOCATION:Potter Room\,  CMS\, Pav.B\, First Floor Common Room (B1.19)
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