CMB Polarization Power Spectra from Two Years of BICEP Data – Cynthia Chiang

Date: Tue. September 22nd, 2009, 11:30 am-12:30 pm
Location: Rockefeller 221

BICEP is a bolometric polarimeter designed to measure the inflationary B-mode polarization of the cosmic microwave background at degree angular scales. During three seasons of observing at the South Pole (2006–2008), BICEP mapped ~2% of the sky chosen to be uniquely clean of polarized foreground emission. I will discuss the initial maps and angular power spectra derived from a subset of the data acquired during the first two years, and I will describe in detail the analysis methods and studies of potential systematic errors. BICEP measures the E-mode power spectrum with high precision at 21 < ell < 335 and detects the acoustic peak expected at ell ~ 140 for the first time. The measured E-mode spectrum is consistent with expectations from a LCDM model, and the B-mode spectrum is consistent with zero. The B-mode spectrum constrains the tensor-to-scalar ratio at r < 0.73 (95% confidence), the first meaningful constraint on the inflationary gravitational wave background to come directly from B-mode polarization.