NRAO/Socorro Colloquium Series
Brian Keating
University of California., San Diego
The discovery of Cosmic Microwave Background B-mode polarization
The week between 10 March 2014 and 17 March 2014 was a remarkable one
for cosmology. This week marked the beginning of a new era of Cosmic
Microwave Background (CMB) measurements. On 10 March 2014, the
POLARBEAR telescope reported evidence for B-mode polarization at
sub-degree scales produced by gravitational lensing of the CMB’s E-mode
polarization. This result followed from one season of observations from
the Atacama Desert (2012-2013). Seven days later, the BICEP2 telescope,
which observed from the South Pole for three seasons (2010–2012),
released results showing an excess of CMB B-modes in the degree-scale
angular range with greater than 5 sigma significance. This excess can
not be explained by instrumental systematics and was confirmed in
cross-correlation with BICEP1 (at 100 and 150 GHz) and preliminary data
from the Keck Array. While a contribution from galactic foreground
cannot be completely excluded, the observed B-mode power spectrum is
well-fit by a lensed Lambda Cold Dark Matter cosmological model with
the addition of primordial tensor fluctuations (gravitational waves). I
will discuss the BICEP2 and POLARBEAR experiments, observations, and
data analyses, as well as current and planned efforts to follow up
these groundbreaking measurements.
December 12, 2014
11:00 am
Array Operations Center Auditorium
All NRAO employees are invited to attend via video, available in Charlottesville Room 245, Green Bank Auditorium, Tucson N525, and VLA Video Conferance Room.
Local Host: Chris Carrilli
