by Lori Appel last modified Feb 05, 2015

NRAO/Socorro Colloquium Series

 Brian Keating

 UC, San Diego

 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.

February 6, 2015

11:00 am

Array Operations Center Auditorium

All NRAO employees are invited to attend via video, available in Charlottesville Auditorium, Green Bank Auditorium, and VLA Video Conference Room.

Local Host:  C. Hales