Abstract
Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This “-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 modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing -mode signal by combining -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 modes measured directly by SPTpol, finding a nonzero correlation at 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.
- Received 22 July 2013
DOI:https://doi.org/10.1103/PhysRevLett.111.141301
© 2013 American Physical Society
Viewpoint
Matter Adds Twist to Cosmic Microwave Background
Published 30 September 2013
A microwave telescope at the South Pole has for the first time captured a particular polarization signal in the cosmic microwave background that arises from gravitational lensing by intervening matter.
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