Detection of Β-mode polarization in the cosmic microwave background with data from the south pole telescope
Johannes Hubmayr, Hsiao-Mei Cho, Gene C. Hilton, Kent D. Irwin, Duncan Hanson
Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "Β-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity- wave signals. In this Letter we present the first detection of gravitational lensing Β modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing Β-mode signal by combining Ε-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the Β modes measured directly by SPTpol, finding a nonzero correlation at 7.7ς significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable.
, Cho, H.
, Hilton, G.
, Irwin, K.
and Hanson, D.
Detection of Β-mode polarization in the cosmic microwave background with data from the south pole telescope, Physical Review Letters, [online], https://doi.org/10.1103/PhysRevLett.111.141301
(Accessed December 8, 2023)