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Mitigating Cosmic Microwave Background Shadow Degradation of Tensor-to-scalar Ratio Measurements through Map-based Studies
- Source :
- The Astrophysical Journal Letters, Vol 949, Iss 2, p L29 (2023)
- Publication Year :
- 2023
- Publisher :
- IOP Publishing, 2023.
-
Abstract
- It has been pointed out that the spurious cosmic microwave background (CMB) B -mode polarization signals caused by the absorption of the CMB monopole component due to the Galactic interstellar matter, called the CMB shadow, degrade the accuracy of detecting the CMB B -mode polarization signals imprinted by primordial gravitational waves. We have made a realistic estimation using simulated sky maps of how the CMB shadow affects forthcoming high-precision CMB B -mode experiments for the first time. The delta-map method, an internal template method taking into account the first-order spatial variation of foregrounds’ spectral parameters, is applied as a foreground-removal method. We show that if the CMB shadow effects are not taken into account in the foreground-removal process, future observations would lead to the false detection of the CMB B -mode polarization signals originating from primordial gravitational waves. We also show that the effect of the CMB shadow can be mitigated by our revised delta-map method to target the CMB B -mode polarization signals at the level of tensor-to-scalar ratio r = 0.001.
Details
- Language :
- English
- ISSN :
- 20418213 and 20418205
- Volume :
- 949
- Issue :
- 2
- Database :
- Directory of Open Access Journals
- Journal :
- The Astrophysical Journal Letters
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.43d1b55fa94125a91244af25dc4f31
- Document Type :
- article
- Full Text :
- https://doi.org/10.3847/2041-8213/acd37d