PhysRevD.83.023507.pdf (187.05 kB)
Improving CMB non-Gaussianity estimators using tracers of local structure
journal contribution
posted on 2023-06-08, 00:59 authored by James M G Mead, Antony LewisAntony Lewis, Lindsay KingLocal non-Gaussianity causes correlations between large-scale perturbation modes and the small-scale power. The large-scale CMB signal has contributions from the integrated Sachs-Wolfe (ISW) effect, which does not correlate with the small-scale power. If this ISW contribution can be removed, the sensitivity to local non-Gaussianity is improved. Gravitational lensing and galaxy counts can be used to trace the ISW contribution; in particular, we show that the CMB lensing potential is highly correlated with the ISW signal. We construct a nearly optimal estimator for the local non-Gaussianity parameter fNL and investigate to what extent we can use this to decrease the variance on fNL. We show that the variance can be decreased by up to 20% at Planck sensitivity using galaxy counts. CMB lensing is a good bias-independent ISW tracer for future more sensitive observations, though the fractional decrease in variance is small if good polarization data are also available.
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- Published
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Journal
Physical Review DISSN
1550-7998Publisher
American Physical SocietyExternal DOI
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2Volume
83Page range
023507Department affiliated with
- Physics and Astronomy Publications
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- Yes
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- Yes
Legacy Posted Date
2012-02-06First Open Access (FOA) Date
2016-03-22First Compliant Deposit (FCD) Date
2016-08-17Usage metrics
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