Is patchy reionization an obstacle in detecting the primordial gravitational wave signal?
| Autor: | S. Paul, Suvodip Mukherjee, Tirthankar Roy Choudhury |
|---|---|
| Přispěvatelé: | Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Lagrange de Paris, Sorbonne Université (SU), Sorbonne Universités |
| Rok vydání: | 2019 |
| Předmět: |
electron
Cosmology and Nongalactic Astrophysics (astro-ph.CO) Cosmic microwave background first stars Cosmic background radiation halo cosmic background radiation: polarization FOS: Physical sciences Astrophysics cosmic background radiation Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences B-mode: primordial cosmic background radiation: B-mode 0103 physical sciences ionization cosmic background radiation: power spectrum dark ages 010303 astronomy & astrophysics Reionization Physics spatial distribution 010308 nuclear & particles physics Gravitational wave gravitational radiation: primordial Astrophysics::Instrumentation and Methods for Astrophysics Spectral density Astronomy and Astrophysics Astrophysics - Astrophysics of Galaxies recombination observatory Amplitude frequency: low Space and Planetary Science efficiency cosmology: observations Astrophysics of Galaxies (astro-ph.GA) Dark Ages reionization Halo history [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2019, 486 (2), pp.2042-2049. ⟨10.1093/mnras/stz1002⟩ Mon.Not.Roy.Astron.Soc. Mon.Not.Roy.Astron.Soc., 2019, 486 (2), pp.2042-2049. ⟨10.1093/mnras/stz1002⟩ |
| ISSN: | 0035-8711 1365-2966 |
| DOI: | 10.48550/arxiv.1903.01994 |
| Popis: | The large-scale CMB B-mode polarization is the direct probe to the low frequency primordial gravitational wave signal. However, unambiguous measurement of this signal requires a precise understanding of the possible contamination. One such potential contamination arises from the patchiness in the spatial distribution of free electrons during the epoch of reionization. We estimate the B-mode power spectrum due to patchy reionization using a combination of \emph{photon-conserving} semi-numerical simulation and analytical calculation, and compare its amplitude with the primordial B-mode signal. For a reionization history which is in agreement with several latest observations, we find that a stronger secondary B-mode polarization signal is produced when the reionization is driven by the sources in massive halos and its amplitude can be comparable to the recombination bump for tensor to scalar ratio $(r) \lesssim 5 \times 10^{-4}$. If contamination from patchy reionization is neglected in the analysis of B-mode polarization data, then for the models of reionization considered in this analysis, we find a maximum bias of about $30\%$ in the value of $r=\,10^{-3}$ when spatial modes between $\ell \in [50, 200]$ are used with a delensing efficiency of $50\%$. The inferred bias from patchy reionization is not a severe issue for the upcoming ground-based CMB experiment Simons Observatory, but can be a potential source of confusion for proposed CMB experiments which target to detect the value of $r< 10^{-3}$. However, this obstacle can be removed by utilizing the difference in the shape of the power spectrum from the primordial signal. 9 pages, 6 figures. Reference added |
| Databáze: | OpenAIRE |
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