Person: Alexander, Kate
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Publication BICEP2 / Keck Array V: Measurements of B-mode Polarization at Degree Angular Scales and 150 GHz by the Keck Array
(IOP Publishing, 2015) Ade, P. A. R.; Ahmed, Z.; Aikin, R. W.; Alexander, Kate; Barkats, D.; Benton, S. J.; Bischoff, Colin; Bock, J. J.; Brevik, J. A.; Buder, I; Bullock, E.; Buza, Victor; Connors, Jake Anthony; Crill, B. P.; Dowell, C. D.; Dvorkin, Cora; Duband, L.; Filippini, J. P.; Fliescher, S.; Golwala, S. R.; Halpern, M.; Harrison, S.; Hasselfield, M.; Hildebrandt, S. R.; Hilton, G. C.; Hristov, V. V.; Hui, H.; Irwin, K. D.; Karkare, Kirit Sukrit; Kaufman, J. P.; Keating, B. G.; Kefeli, S.; Kernasovskiy, S. A.; Kovac, John; Kuo, C. L.; Leitch, E. M.; Lueker, M.; Mason, P.; Megerian, K. G.; Netterfield, C. B.; Nguyen, H. T.; O’Brient, R.; Ogburn IV, R. W.; Orlando, A.; Pryke, C.; Reintsema, C. D.; Richter, Sonja Valeska; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z. K.; Sudiwala, R. V.; Teply, G. P.; Thompson, K. L.; Tolan, J. E.; Turner, A. D.; Vieregg, A. G.; Weber, A. C.; Willmert, J.; Wong, C. L.; Yoon, K. W.The Keck Array is a system of cosmic microwave background polarimeters, each similar to the Bicep2 experiment. In this paper we report results from the 2012 to 2013 observing seasons, during which the Keck Array consisted of five receivers all operating in the same (150 GHz) frequency band and observing field as Bicep2. We again find an excess of B-mode power over the lensed-ΛCDM expectation of >5σ in the range 30 < ℓ < 150 and confirm that this is not due to systematics using jackknife tests and simulations based on detailed calibration measurements. In map difference and spectral difference tests these new data are shown to be consistent with Bicep2. Finally, we combine the maps from the two experiments to produce final Q and U maps which have a depth of 57 nK deg (3.4 μK arcmin) over an effective area of 400 deg(2) for an equivalent survey weight of 250,000 μK(−)(2). The final BB band powers have noise uncertainty a factor of 2.3 times better than the previous results, and a significance of detection of excess power of >6σ.
Publication Bicep2/keck Array. Vii. Matrix Basede/bseparation Applied to Bicep2 and the Keck Array
(American Astronomical Society, 2016) Ade, P. A. R.; Ahmed, Z.; Aikin, R. W.; Alexander, Kate; Barkats, Denis; Benton, S. J.; Bischoff, Colin; Bock, J. J.; Bowens-Rubin, Rachel; Brevik, J. A.; Buder, I; Bullock, E.; Buza, Victor; Connors, Jake Anthony; Crill, B. P.; Duband, L.; Dvorkin, Cora; Filippini, J. P.; Fliescher, S.; Grayson, J.; Halpern, M.; Harrison, Sarah; Hildebrandt, S. R.; Hilton, G. C.; Hui, H.; Irwin, K. D.; Kang, J.; Karkare, Kirit Sukrit; Karpel, E.; Kaufman, J. P.; Keating, B. G.; Kefeli, S.; Kernasovskiy, S. A.; Kovac, John; Kuo, C. L.; Leitch, E. M.; Lueker, M.; Megerian, K. G.; Namikawa, T.; Netterfield, C. B.; Nguyen, H. T.; O’Brient, R.; IV, R. W. Ogburn; Orlando, A.; Pryke, C.; Richter, S.; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z. K.; Steinbach, B.; Sudiwala, R. V.; Teply, G. P.; Thompson, K. L.; Tolan, J. E.; Tucker, C.; Turner, A. D.; Vieregg, A. G.; Weber, A. C.; Wiebe, D. V.; Willmert, J.; Wong, C; Wu, W. L. K.; Yoon, K. W.A linear polarization field on the sphere can be uniquely decomposed into an E-mode and a B-mode component. These two components are analytically defined in terms of spin-2 spherical harmonics. Maps that contain filtered modes on a partial sky can also be decomposed into E-mode and B-mode components. However, the lack of full sky information prevents orthogonally separating these components using spherical harmonics. In this paper, we present a technique for decomposing an incomplete map into E and B-mode components using E and B eigenmodes of the pixel covariance in the observed map. This method is found to orthogonally define E and B in the presence of both partial sky coverage and spatial filtering. This method has been applied to the Bicep2 and the Keck Array maps and results in reducing E to B leakage from ΛCDM E-modes to a level corresponding to a tensor-to-scalar ratio of