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Information content of the lensed CMB power spectra

Challinor, Anthony and Lewis, Antony and Rocha, Graça and Smith, Sarah (2007) Information content of the lensed CMB power spectra. New Astronomy Reviews, 51 (3-4). pp. 421-430. ISSN 1387-6473. doi:10.1016/j.newar.2006.11.070.

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Weak lensing of the cosmic microwave background (CMB) is expected to be detected with the next generation of observations. We review recent theoretical refinements in the calculation of the lensed spectra and discuss the extent to which these corrections are required to avoid parameter biases from future data. For a future satellite mission (with ~ 1 μK′ sensitivity), targeting large-angle B modes from gravitational waves, the flat-sky and gradient approximations must be dropped and non-linear matter clustering included if r is near the detection threshold (r ~ 2 × 10^(−4)). We also discuss the role of the lensed CMB spectra in constraining cosmological parameters, such as light neutrino masses and the dark energy model, that are essentially degenerate with respect to the primary CMB fluctuations. Non-Gaussianities and degeneracies limit what can be learned from the lensed spectra, but a simple power spectrum analysis will still be a worthwhile first step. Analysing futuristic, cosmic-variance-limited lensed B-mode spectra requires careful attention to the choice of likelihood approximation. We show that approximations in current use for the analysis of Gaussian fields produce biased results on lensed simulations. We highlight a more refined approximation that performs significantly better.

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Rocha, Graça0000-0002-4150-8076
Additional Information:© 2006 Elsevier B.V. Available online 18 January 2007. A.C. acknowledges a Royal Society Research Fellowship and A.L. a PPARC Advanced Fellowship. S.S. acknowledges support from a PPARC studentship and the Cavendish Laboratory during this work. G.R. was supported by a Leverhulme Fellowship during the early stages of this work. Some of the results in this paper have been derived using the HEALPix package (Gorski et al., 2005). A.C. also expresses his thanks to the organisers of this memorable conference.
Funding AgencyGrant Number
Royal Society Research FellowshipUNSPECIFIED
Particle Physics and Astronomy Research Council (PPARC) Advanced FellowshipUNSPECIFIED
Particle Physics and Astronomy Research Council (PPARC) studentshipUNSPECIFIED
Cavendish LaboratoryUNSPECIFIED
Leverhulme FellowshipUNSPECIFIED
Issue or Number:3-4
Record Number:CaltechAUTHORS:20100503-134527383
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:18112
Deposited By: Tony Diaz
Deposited On:05 May 2010 04:25
Last Modified:08 Nov 2021 23:41

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