Searching for Anisotropic Cosmic Birefringence with Polarization Data from SPTpol

• Published in: Physical Review D
• Main Authors: Bianchini, F., Wu, W. L. K., Ade, P. A. R., Anderson, A. J., Austermann, J. E., Avva, J. S., Balkenhol, L., Beall, J A, Baxter, E., Bender, A. N., Bleem, L. E., Carlstrom, J. E., Chang, C. L., Henning, J. W., Novosad, V., Wang, G., Yefremenko, V.
• Language: unknown
• Published: 2022
• Subjects: South Pole; Hubble; South pole
• Online Access: http://www.osti.gov/servlets/purl/1774113; https://www.osti.gov/biblio/1774113; https://doi.org/10.1103/PhysRevD.102.083504

We present a search for anisotropic cosmic birefringence in 500 deg2 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 non-detection is translated into an upper limit on the amplitude of the scale-invariant cosmic rotation power spectrum, L(L+1)CααL/2π<0.10×10-4 rad2 (0.033 deg2, 95% C.L.). This upper limit can be used to place constraints on the strength of primordial magnetic fields, B1Mpc<17nG (95% C.L.), and on the coupling constant of the Chern-Simons electromagnetic term gaγ<4.0×10-2/HI (95% C.L.), where HI 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 non-vanishing in certain theoretical scenarios, and find no detectable signal. We perform a suite of systematics and consistency checks and find no evidence for contamination.