Measurements of B-mode Polarization of the Cosmic Microwave Background from 500 Square Degrees of SPTpol Data

• Main Authors: Sayre, J. T., Reichardt, C. L., Henning, J. W., Ade, P. A. R., Anderson, A. J., Austermann, J. E., Avva, J. S., Beall, J. A., Bender, A. N., Benson, B. A., Bianchini, F., Bleem, L. E., Carlstrom, J. E., Chang, C. L., Chiang, H. C., Citron, R., Moran, C. Corbett, Crawford, T. M., Crites, A. T., de Haan, T., Dobbs, M. A., Everett, W., Gallicchio, J., George, E. M., Gilbert, A., Gupta, N., Halverson, N. W., Harrington, N., Hilton, G. C., Holder, G. P., Holzapfel, W. L., Hrubes, J. D., Huang, N., Hubmayr, J., Irwin, K. D., Knox, L., Lee, A. T., Li, D., Lowitz, A., McMahon, J. J., Meyer, S. S., Mocanu, L. M., Montgomery, J., Nadolski, A., Natoli, T., Nibarger, J. P., Noble, G., Novosad, V., Padin, S., Patil, S., Pryke, C., Ruhl, J. E., Saliwanchik, B. R., Schaffer, K. K., Sievers, C., Smecher, G., Stark, A. A., Tucker, C., Vanderlinde, K., Veach, T., Vieira, J. D., Wang, G., Whitehorn, N., Wu, W. L. K., Yefremenko, V.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: arXiv 2019
• Subjects: Cosmology and Nongalactic Astrophysics astro-ph.CO; FOS Physical sciences; South Pole; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.1910.05748; https://arxiv.org/abs/1910.05748

We report a B-mode power spectrum measurement from the cosmic microwave background (CMB) polarization anisotropy observations made using the SPTpol instrument on the South Pole Telescope. This work uses 500 deg$^2$ of SPTpol data, a five-fold increase over the last SPTpol B-mode release. As a result, the bandpower uncertainties have been reduced by more than a factor of two, and the measurement extends to lower multipoles: $52 < \ell < 2301$. Data from both 95 and 150 GHz are used, allowing for three cross-spectra: 95 GHz x 95 GHz, 95 GHz x 150 GHz, and 150 GHz x 150 GHz. B-mode power is detected at very high significance; we find $P(BB < 0) = 5.8 \times 10^{-71}$, corresponding to a $18.1 σ$ detection of power. An upper limit is set on the tensor-to-scalar ratio, $r < 0.44$ at 95% confidence (the expected $1 σ$ constraint on $r$ given the measurement uncertainties is 0.22). We find the measured B-mode power is consistent with the Planck best-fit $Λ$CDM model predictions. Scaling the predicted lensing B-mode power in this model by a factor Alens, the data prefer Alens = $1.17 \pm 0.13$. These data are currently the most precise measurements of B-mode power at $\ell > 320$. : 16 pages, 4 figures, Submitted to PRD