Characterizing the Epoch of Reionization with the small-scale CMB: constraints on the optical depth and physical parameters

Abstract

Patchy reionization leaves a number of imprints on the small-scale cosmic microwave background (CMB) temperature fluctuations, the largest of which is the kinematic Sunyaev-Zel'dovich (kSZ), the Doppler shift of CMB photons scattering off moving electrons in ionized bubbles. It has long been known that in the CMB power spectrum, this imprint of reionization is largely degenerate with the kSZ signal produced by late-time galaxies and clusters, thus limiting our ability to constrain reionization. Following Smith & Ferraro (2017), it is possible to isolate the reionization contribution in a model independent way, by looking at the large scale modulation of the small scale CMB power spectrum. In this paper we extend the formalism to use the full shape information of the small scale power spectrum (rather than just its broadband average), and argue that this is necessary to break the degeneracy between the optical depth $\tau$ and parameters setting the duration of reionization. In particular, we show that the next generation of CMB experiments could achieve up to a factor of 3 improvement on the optical depth $\tau$ and at the same time, constrain the duration of reionization to $\sim$ 25 %. This can help tighten the constrains on neutrino masses, which will be limited by our knowledge of $\tau$, and shed light on the physical processes responsible for reionization.

8 pages, 3 figures. Comments welcome

References in corpus (4)

• Model-independent evidence in favor of an end to reionization by z~6
• Neutrino cosmology and Planck
• Emulating Simulations of Cosmic Dawn for 21cm Power Spectrum Constraints on Cosmology, Reionization, and X-ray Heating
• Detection of the pairwise kinematic Sunyaev-Zel'dovich effect with BOSS DR11 and the Atacama Cosmology Telescope

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• Neutrino Mass from Cosmology: Probing Physics Beyond the Standard Model
• Projected-Field Kinetic Sunyaev-Zel'dovich Cross-Correlations: Halo Model and Forecasts
• Future Constraints on the Reionization History and the Ionizing Sources from Gamma-ray Burst Afterglows
• First Constraints on the Epoch of Reionization Using the non-Gaussianity of the Kinematic Sunyaev-Zel{'}dovich Effect from the South Pole Telescope and {\it Herschel}-SPIRE Observations
• Dispu$\tau$able: the high cost of a low optical depth
• Inevitable imprints of patchy reionization on the cosmic microwave background anisotropy
• Patchy Kinetic Sunyaev-Zel'dovich Effect with Controlled Reionization History and Morphology
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• Prospects for kSZ${}^2$-Galaxy Cross-Correlations during Reionization
• Optical depth to reionization from perturbative 21cm clustering
• Probing helium reionization with kinetic Sunyaev Zel'dovich tomography
• New Interpretations of the Cosmological Preference for a Negative Neutrino Mass
• Cosmology at high redshift -- a probe of fundamental physics
• A forecast of the sensitivity on the measurement of the optical depth to reionization with the GroundBIRD experiment
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• Atacama Large Aperture Submillimeter Telescope (AtLAST) Science: Resolving the Hot and Ionized Universe through the Sunyaev-Zeldovich effect
• Reconstructing patchy helium reionization using the cosmic microwave background and large-scale structure
• Cosmic variance mitigation in measurements of the integrated Sachs-Wolfe effect
• Cosmological Implications of a Neutrino Mass Detection
• Cross-correlating the patchy screening and kinetic Sunyaev-Zel'dovich effects as a new probe of reionization
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