Searching for anisotropic cosmic birefringence with polarization data from SPTpol

Abstract

We present a search for anisotropic cosmic birefringence in 500 deg 2 of southern sky observed at 150 GHz with the SPTpol camera on the South Pole Telescope. We reconstruct a map of cosmic polarization rotation anisotropies using higher-order correlations between the observed cosmic microwave background (CMB) E and B fields. We then measure the angular power spectrum of this map, which is found to be consistent with zero. The nondetection is translated into an upper limit on the amplitude of the scale-invariant cosmic rotation power spectrum, LðL þ 1ÞC αα L =2π < 0.10 × 10 −4 rad 2 (0.033 deg 2 , 95% C.L.). This upper limit can be used to place constraints on the strength of primordial magnetic fields, B 1 Mpc < 17 nG (95% C.L.), and on the coupling constant of the Chern-Simons electromagnetic term g aγ < 4.0 × 10 −2 =H I (95% C.L.), where H I is the inflationary Hubble scale. For the first time, we also cross-correlate the CMB temperature fluctuations with the reconstructed rotation angle map, a signal expected to be nonvanishing in certain theoretical scenarios, and find no detectable signal. We perform a suite of systematics and consistency checks and find no evidence for contamination.

Instrumental systematics biases in CMB lensing reconstruction: A simulation-based assessment

“…V). Other experiments, such as ACTPol and SPTpol, have reported lower mean values for the polarization angle errors consistent with ∆ψ ∼ 0.5 • [51,52]. Although we do not consider this case in detail for estimating lensing biases, we give a comparison between setup A and an ACTPol-like setup with ∆ψ drawn from N (−0.5 • , 2.0 • ) ("setup B") in Secs.…”

Cosmic Birefringence from Planck Data Release 4

“…[17][18][19][20][21][22][23][24] discuss possible cosmological implications of this particular measurement, and Refs. [25][26][27][28][29][30][31] give previous constraints on β. In this paper, we apply the analysis method of Ref.…”

New physics from the polarised light of the cosmic microwave background

“…Fluctuations in β ( n) are easier to measure experimentally than the isotropic β , as they do not require knowledge of the absolute PA of polarisation-sensitive detectors on the focal plane with respect to the sky 88 . Currently there is no evidence for fluctuations in β ( n) [89][90][91][92] ; thus, we focus on the isotropic β for the rest of this article.…”

“…If we rotate the focal plane by a miscalibration angle α, the observed PA shifts and generates non-zero C EB,o in the same way as β . As a result, in the absence of any other information, we can only determine the sum of the two angles, α + β , which explains why the previous determinations of β were spread over a wide range beyond the quoted statistical uncertainties (excluding systematic uncertainties in the knowledge of α) 16,57,90,91,118 .…”