New developments in the BICEP program and the next era of deep CMB polarimetry

by Zeeshan Ahmed (Stanford University)

Monday 11 May 2015, 13:00 → 14:00 US/Pacific

Kavli Auditorium (SLAC)

The BICEP/Keck Array program comprises a series of telescopes at the South Pole designed to measure cosmic microwave background polarization on degree angular scales, in search of imprints of inflation. This talk will describe the instrumentation, latest science results and recent improvements enabling further scale up of the program. Using data collected through 2013 at 150 GHz, the BICEP2+Keck Array polarization maps achieve noise levels of 3.4 microK arcmin over an area of 400 deg^2. A strong excess above the lensing B-mode signal predicted by Lambda-CDM is observed, but a joint analysis with Planck finds the excess to consist of at least half galactic dust foreground. A 95% confidence upper limit on inflationary tensor-to-scalar ratio, r<0.12 is obtained. Further improvement in constraints mandates multi-frequency observations for foreground control, which the Keck Array has implemented with 95 GHz and 220 GHz receivers in 2014 and 2015 respectively. Additionally, we have developed and in January 2015 fielded BICEP3, a single 95 GHz receiver with ~10x optical throughput and sensitivity compared to BICEP2. The various instrumental improvements pioneered in BICEP3 present a path forward to deeper large-sky CMB surveys for both inflation and lensing science in the coming decade.