Secondary CMB anisotropies from magnetized haloes - I. Power spectra of the Faraday rotation angle and conversion rate
| Autor: | F. Lacasa, G. Hurier, N. Lemarchand, Agnès Ferté, J. Grain |
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| Přispěvatelé: | Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
FOS: Physical sciences Astrophysics Electron Astrophysics::Cosmology and Extragalactic Astrophysics cosmic background radiation Rotation 7. Clean energy 01 natural sciences law.invention symbols.namesake law cosmology: theory 0103 physical sciences Faraday effect Faraday cage 010303 astronomy & astrophysics Circular polarization Physics 010308 nuclear & particles physics Linear polarization Astronomy and Astrophysics 3. Good health Magnetic field Computational physics 13. Climate action Space and Planetary Science symbols Halo large-scale structure of Universe [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 630, pp.A149. ⟨10.1051/0004-6361/201834485⟩ Astron.Astrophys. Astron.Astrophys., 2019, 630, pp.A149. ⟨10.1051/0004-6361/201834485⟩ |
| ISSN: | 0004-6361 |
| Popis: | Magnetized plasmas within halos of galaxies leave their footprint on the polarized anisotropies of the cosmic microwave background. The two dominant effects for astrophysical halos are Faraday rotation generating rotation of the plane of linear polarization, and Faraday conversion inducing a leakage from linear polarization to circular polarization. We revisit these sources of secondary anisotropies by computing the angular power spectra of the Faraday rotation angle and of the Faraday conversion rate by the large scale structures. To this end, we use the halo model and we pay special attention to the impact of magnetic field projections. Assuming magnetic fields of halos to be uncorrelated, we found a vanishing 2-halo term, and angular power spectra peaking at multipoles $\ell\sim10^4$. The Faraday rotation angle is dominated by the contribution of thermal electrons. For the Faraday conversion rate, we found that both thermal electrons and relativistic, non-thermal electrons contribute equally in the most optimistic case for the density and Lorentz factor of relativistic electrons, while in more pessimistic cases the thermal electrons give the dominant contribution. Assuming the magnetic field to be independent of the halo mass, the angular power spectra for both effects roughly scale with the amplitude of matter perturbations as $\sim\sigma_8^3$, and with a very mild dependence with the density of cold dark matter. Introducing a dependence of the magnetic field strength with the halo mass leads to an increase of the scaling with the amplitude of matter fluctuations, up to $\sim\sigma_8^{9.5}$ for Faraday rotation and $\sim\sigma_8^{15}$ for Faraday conversion for a magnetic field strength scaling linearly with the halo mass. Comment: 13 + 5 pages, 6 figures, 2 tables |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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