Journal article
Impact of Galactic dust non-Gaussianity on searches for B-modes from inflation
- Abstract:
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A key challenge in the search for primordial B-modes is the presence of polarized Galactic foregrounds, especially thermal dust emission. Power-spectrum-based analysis methods generally assume the foregrounds to be Gaussian random fields when constructing a likelihood and computing the covariance matrix. In this paper, we investigate how non-Gaussianity in the dust field instead affects CMB and foreground parameter inference in the context of inflationary B-mode searches, capturing this effect via modifications to the dust power-spectrum covariance matrix. For upcoming experiments such as the Simons Observatory, we find no dependence of the tensor-to-scalar ratio uncertainty σ(r)on the degree of dust non-Gaussianity or the nature of the dust covariance matrix. We provide an explanation of this result, noting that when frequency decorrelation is negligible, dust in mid-frequency channels is cleaned using high-frequency data in a way that is independent of the spatial statistics of dust. We show that our results hold also for non-zero levels of frequency decorrelation that are compatible with existing data. We find, however, that neglecting the impact of dust non-Gaussianity in the covariance matrix can lead to inaccuracies in goodness-of-fit metrics. Care must thus be taken when using such metrics to test B-mode spectra and models, although we show that any such problems can be mitigated by using only cleaned spectrum combinations when computing goodness-of-fit statistics.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, pdf, 3.5MB, Terms of use)
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- Publisher copy:
- 10.1093/mnras/stad3529
Authors
- Funder identifier:
- https://ror.org/057g20z61
- Grant:
- ST/W000903/1
- ST/P004474/2
- ST/P004474/1
- Publisher:
- Oxford University Press
- Journal:
- Monthly Notices of the Royal Astronomical Society More from this journal
- Volume:
- 527
- Issue:
- 3
- Pages:
- 5751-5766
- Publication date:
- 2023-11-15
- Acceptance date:
- 2023-11-13
- DOI:
- EISSN:
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1365-2966
- ISSN:
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0035-8711
- Language:
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English
- Keywords:
- Pubs id:
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1592553
- Local pid:
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pubs:1592553
- Deposit date:
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2025-05-07
- ARK identifier:
Terms of use
- Copyright holder:
- Abril-Cabezas et al.
- Copyright date:
- 2023
- Rights statement:
- © The Author(s) 2023. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
- Licence:
- CC Attribution (CC BY)
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