Measurements of B-mode polarization of the cosmic microwave background from 500 square degrees of SPTpol data

• Published in: Physical Review D
• 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., Chaubal, P., 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: English
• Published: American Physical Society 2020
• Subjects: South Pole; South pole
• Online Access: https://authors.library.caltech.edu/104000/; https://authors.library.caltech.edu/104000/1/PhysRevD.101.122003.pdf; https://authors.library.caltech.edu/104000/2/1910.05748.pdf; https://resolver.caltech.edu/CaltechAUTHORS:20200624-104211777

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 deg² 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 < ℓ < 2301. Data from both 95 and 150 GHz are used, allowing for three cross-spectra: 95 GHz × 95 GHz, 95 GHz × 150 GHz, and 150 GHz × 150 GHz. B-mode power is detected at very high significance; we find P(BB < 0) = 5.8 × 10⁻⁷¹, corresponding to a 18.1σ detection of power. With a prior on the galactic dust from Planck, WMAP and BICEP2/Keck observations, the SPTpol B-mode data can be used to set an upper limit on the tensor-to-scalar ratio, r < 0.44 at 95% confidence (the expected 1σ 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 A_(lens), the data prefer A_(lens) = 1.17 ± 0.13. These data are currently the most precise measurements of B-mode power at ℓ > 320.