Implications of the Cosmic Background Imager Polarization Data

Abstract

We present new measurements of the power spectra of the E-mode of CMB\npolarization, the temperature T, the cross-correlation of E and T, and upper\nlimits on the B-mode from 2.5 years of dedicated Cosmic Background Imager (CBI)\nobservations. Both raw maps and optimal signal images in the uv-plane and real\nspace show strong detections of the E-mode (11.7 sigma for the EE power\nspectrum overall) and no detection of the B-mode. The power spectra are used to\nconstrain parameters of the flat tilted adiabatic Lambda-CDM models: those\ndetermined from EE and TE bandpowers agree with those from TT, a powerful\nconsistency check. There is little tolerance for shifting polarization peaks\nfrom the TT-forecast locations, as measured by the angular sound crossing scale\ntheta = 100 ell_s = 1.03 +/- 0.02 from EE and TE cf. 1.044 +/- 0.005 with the\nTT data included. The scope for extra out-of-phase peaks from subdominant\nisocurvature modes is also curtailed. The EE and TE measurements of CBI, DASI\nand BOOMERANG are mutually consistent, and, taken together rather than singly,\ngive enhanced leverage for these tests.\n