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School of Physics and Astronomy

The discovery of primordial B-mode polarization

13 June 2014

Time: 10:00am
Venue: Engineering 325

Astronomy Unit Seminars
Prof. Brian G. Keating (University of California, San Diego )
Alexandre Polnarev

The era of Cosmic Microwave Background B-mode polarization cosmology has recently begun. The BICEP2 telescope was a small refracting telescope which observed from the South Pole for three seasons. In March 2014, BICEP2 released results showing an excess of B-modes in the degree angular scale range with >5 sigma significance. We find that this excess can not be explained by instrumental systematics or foregrounds. The signal was confirmed in cross-correlation with BICEP1 (at 100 and 150 GHz) and preliminary data from the Keck Array. The observed B-mode power spectrum is well-fit by a lensed-LCDM cosmological model with the addition of primordial tensor fluctuations with tensor-to-scalar ratio r=0.20^{+0.07}_{-0.05}. I will discuss the BICEP2 experiment, observations, and data analysis, as well as current and planned efforts to follow up this detection.