Patchy screening of the cosmic microwave background by inhomogeneous reionization
We derive a constraint on patchy screening of the cosmic microwave background from inhomogeneous reionization using off-diagonal TB and TT correlations in WMAP-7 temperature/polarization data. We interpret this as a constraint on the rms optical-depth fluctuation Δτ as a function of a coherence multipole L_C. We relate these parameters to a comoving coherence scale, of bubble size R_C, in a phenomenological model where reionization is instantaneous but occurs on a crinkly surface, and also to the bubble size in a model of "Swiss cheese" reionization where bubbles of fixed size are spread over some range of redshifts. The current WMAP data are still too weak, by several orders of magnitude, to constrain reasonable models, but forthcoming Planck and future EPIC data should begin to approach interesting regimes of parameter space. We also present constraints on the parameter space imposed by the recent results from the EDGES experiment.
Additional Information© 2013 American Physical Society. Received 1 November 2012; published 27 February 2013. The authors thank Gil Holder for useful discussions. This work was supported by the Simons Foundation at Caltech, Grant No. DoESC-0008108 and NASA Grant No. NNX12AE86G at Caltech, and a CITA National Fellowship at McGill. Some of the results in this paper have been derived using HEALPix .
Published - PhysRevD.87.047303.pdf
Submitted - 1210.5507.pdf