Measurements of Degree-Scale B-mode Polarization with the BICEP/Keck
  Experiments at South Pole
  The BICEP and Keck Array experiments are a suite of small-aperture refracting
telescopes observing the microwave sky from the South Pole. They target the
degree-scale B-mode polarization signal imprinted in the Cosmic Microwave
Background (CMB) by primordial gravitational waves. Such a measurement would
shed light on the physics of the very early universe. While BICEP2 observed for
the first time a B-mode signal at 150 GHz, higher frequencies from the Planck
satellite showed that it could be entirely due to the polarized emission from
Galactic dust, though uncertainty remained high. Keck Array has been observing
the same region of the sky for several years, with an increased detector count,
producing the deepest polarized CMB maps to date. New detectors at 95 GHz were
installed in 2014, and at 220 GHz in 2015. These observations enable a better
constraint of galactic foreground emissions, as presented here. In 2015, BICEP2
was replaced by BICEP3, a 10 times higher throughput telescope observing at 95
GHz, while Keck Array is now focusing on higher frequencies. In the near
future, BICEP Array will replace Keck Array, and will allow unprecedented
sensitivity to the gravitational wave signal. High resolution observations from
the South Pole Telescope (SPT) will also be used to remove the lensing
contribution to B-modes.
