Year: 2009
Type: article
Abstract: $B$ modes in CMB polarization from patchy reionization arise from two effects: generation of polarization from scattering of quadrupole moments by reionization bubbles and fluctuations in the screening of $E$ modes from recombination. The scattering contribution has been studied previously, but the screening contribution has not yet been calculated. We show that on scales smaller than the acoustic scale ($\ensuremath{\ell}\ensuremath{\gtrsim}300$), the $B$-mode power from screening is larger than the $B$-mode power from scattering. The ratio approaches a constant $\ensuremath{\sim}2.5$ below the damping scale ($\ensuremath{\ell}\ensuremath{\gtrsim}2000$). On degree scales relevant for gravitational waves ($\ensuremath{\ell}\ensuremath{\lesssim}100$), screening $B$ modes have a white noise tail and are subdominant to the scattering effect. These results are robust to uncertainties in the modeling of patchy reionization.
Authors: Cora Dvorkin, Wayne Hu, Kendrick M. Smith
Institutions: University of Chicago, University of Cambridge
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1967701424