Lensing bias to CMB polarization measurements of compensated isocurvature perturbations
| Autor: | Chen Heinrich |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
Cosmology and Nongalactic Astrophysics (astro-ph.CO) 010308 nuclear & particles physics Dark matter Cosmic microwave background FOS: Physical sciences Observable Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences Cosmology Baryon Baryogenesis Gravitational lens 0103 physical sciences Multipole expansion 010303 astronomy & astrophysics Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | Physical Review D. 97 |
| ISSN: | 2470-0029 2470-0010 |
| Popis: | Compensated isocurvature perturbations are opposite spatial fluctuations in the baryon and dark matter (DM) densities. They arise in the curvaton model and some models of baryogenesis. While the gravitational effects of baryon fluctuations are compensated by those of DM, leaving no observable impacts on the cosmic microwave background (CMB) at first order, they modulate the sound horizon at recombination, thereby correlating CMB anisotropies at different multipoles. As a result, CIPs can be reconstructed using quadratic estimators similarly to CMB detection of gravitational lensing. Because of these similarities, however, the CIP estimators are biased with lensing contributions that must be subtracted. These lensing contributions for CMB polarization measurement of CIPs are found to roughly triple the noise power of the total CIP estimator on large scales. In addition, the cross power with temperature and $E$-mode polarization are contaminated by lensing-ISW (integrated Sachs-Wolfe) correlations and reionization-lensing correlations respectively. For a cosmic-variance-limited (CVL) temperature and polarization experiment measuring out to multipoles $l_{\max} = 2500$, the lensing noise raises the detection threshold by a factor of 1.5, leaving a $2.7\sigma$ detection possible for the maximal CIP signal in the curvaton model. Comment: 11 pages, 10 figures |
| Databáze: | OpenAIRE |
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