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SLAC Publication: SLAC-PUB-16741
SLAC Release Date: March 6, 2017
Measurements of Sub-degree B-mode Polarization in the Cosmic Microwave Background from 100 Square Degrees of SPTpol Data
Keisler, R..
We present a measurement of the B-mode polarization power spectrum (the BB spectrum) from 100 \mathrm{deg}^2 of sky observed with SPTpol, a polarization-sensitive receiver currently installed on the South Pole Telescope. The observations used in this work were taken during 2012 and early 2013 and include data in spectral bands centered at 95 and 150 GHz. We report the BB spectrum in five bins in multipole space, spanning the range 300 \le \ell \le 2300, and for three spectral combinations: 95 GH... Show Full Abstract
We present a measurement of the B-mode polarization power spectrum (the BB spectrum) from 100 \mathrm{deg}^2 of sky observed with SPTpol, a polarization-sensitive receiver currently installed on the South Pole Telescope. The observations used in this work were taken during 2012 and early 2013 and include data in spectral bands centered at 95 and 150 GHz. We report the BB spectrum in five bins in multipole space, spanning the range 300 \le \ell \le 2300, and for three spectral combinations: 95 GHz \times 95 GHz, 95 GHz \times 150 GHz, and 150 GHz \times 150 GHz. We subtract small (< 0.5 \sigma in units of statistical uncertainty) biases from these spectra and account for the uncertainty in those biases. The resulting power spectra are inconsistent with zero power but consistent with predictions for the BB spectrum arising from the gravitational lensing of E-mode polarization. If we assume no other source of BB power besides lensed B modes, we determine a preference for lensed B modes of 4.9 \sigma. After marginalizing over tensor power and foregrounds, namely polarized emission from galactic dust and extragalactic sources, this significance is 4.3 \sigma. Fitting for a single parameter, A_\mathrm{lens}, that multiplies the predicted lensed B-mode spectrum, and marginalizing over tensor power and foregrounds, we find A_\mathrm{lens} = 1.08 \pm 0.26, indicating that our measured spectra are consistent with the signal expected from gravitational lensing. The data presented here provide the best measurement to date of the B-mode power spectrum on these angular scales. Show Partial Abstract
  • Interest Categories: Astrophysics