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Published March 10, 2014 | Published + Submitted
Journal Article Open

Degree-scale Cosmic Microwave Background Polarization Measurements from Three Years of BICEP1 Data


BICEP1 is a millimeter-wavelength telescope designed specifically to measure the inflationary B-mode polarization of the cosmic microwave background at degree angular scales. We present results from an analysis of the data acquired during three seasons of observations at the South Pole (2006-2008). This work extends the two-year result published in Chiang et al., with additional data from the third season and relaxed detector-selection criteria. This analysis also introduces a more comprehensive estimation of band power window functions, improved likelihood estimation methods, and a new technique for deprojecting monopole temperature-to-polarization leakage that reduces this class of systematic uncertainty to a negligible level. We present maps of temperature, E- and B-mode polarization, and their associated angular power spectra. The improvement in the map noise level and polarization spectra error bars are consistent with the 52% increase in integration time relative to Chiang et al. We confirm both self-consistency of the polarization data and consistency with the two-year results. We measure the angular power spectra at 21 ≤ ℓ ≤ 335 and find that the EE spectrum is consistent with Lambda cold dark matter cosmology, with the first acoustic peak of the EE spectrum now detected at 15σ. The BB spectrum remains consistent with zero. From B-modes only, we constrain the tensor-to-scalar ratio to r = 0.03^(+0.27)_(-0.23), or r < 0.70 at 95% confidence level.

Additional Information

© 2014 American Astronomical Society. Received 2013 October 4; accepted 2014 January 7; published 2014 February 14. Bicep1 was supported by NSF grant No. OPP-0230438, Caltech President's Discovery Fund, Caltech President's Fund PF-471, JPL Research and Technology Development Fund, and the late J. Robinson. This analysis was supported in part by NSF CAREER award No. AST-1255358 and the Harvard College Observatory, and J.M.K. acknowledges support from an Alfred P. Sloan Research Fellowship. B.G.K acknowledges support from NSF PECASE Award No. AST-0548262. We thank the South Pole Station staff for helping make our observing seasons a success.We also thank our colleagues in Acbar, Boomerang, QUaD, Bolocam, SPT, WMAP, and Planck for advice and helpful discussions, and Kathy Deniston and Irene Coyle for logistical and administrative support. We thank Patrick Shopbell for computational support at Caltech and the FAS Science Division Research Computing Group at Harvard University for providing support to run all the computations for this paper on the Odyssey cluster.

Attached Files

Published - 0004-637X_783_2_67.pdf

Submitted - 1310.1422v2.pdf


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