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Kirit Karkare (Harvard) "B-Mode Polarization Results from BICEP/Keck Array and Beam Systematics in Current and Next-Generation CMB Experiments"
January 19, 2017 @ 4:00 pm - 5:00 pm
Abstract:
The BICEP/Keck Array cosmic microwave background (CMB) polarization experiments located at the South Pole are a series of small-aperture refracting telescopes focused on the degree-scale B-mode signature of inflationary gravitational waves. I will present our latest results which have produced the most stringent constraints on the tensor-to-scalar ratio to date: sigma(r) = 0.024 and r < 0.09 from B-modes alone (r < 0.07 in combination with other datasets). These constraints will rapidly improve with upcoming measurements at the multiple frequencies needed to separate Galactic foregrounds from the CMB, and in combination with higher-resolution experiments to remove B-modes induced by gravitational lensing. I will provide an update on our expanded frequency coverage and plans for future receivers.
Next-generation CMB experiments with hundreds of thousands of detectors will require exquisite control of instrumental systematics. I will review key aspects of the BICEP/Keck instrument design which maximize polarization sensitivity and reduce systematics at large angular scales, including the ability to measure beams in the far field with high precision. Finally, I will discuss the prospects for dealing with temperature-to-polarization leakage in future experiments, and how the beams systematics levels we achieve with current instrument and analysis technology will scale with detector count.
The BICEP/Keck Array cosmic microwave background (CMB) polarization experiments located at the South Pole are a series of small-aperture refracting telescopes focused on the degree-scale B-mode signature of inflationary gravitational waves. I will present our latest results which have produced the most stringent constraints on the tensor-to-scalar ratio to date: sigma(r) = 0.024 and r < 0.09 from B-modes alone (r < 0.07 in combination with other datasets). These constraints will rapidly improve with upcoming measurements at the multiple frequencies needed to separate Galactic foregrounds from the CMB, and in combination with higher-resolution experiments to remove B-modes induced by gravitational lensing. I will provide an update on our expanded frequency coverage and plans for future receivers.
Next-generation CMB experiments with hundreds of thousands of detectors will require exquisite control of instrumental systematics. I will review key aspects of the BICEP/Keck instrument design which maximize polarization sensitivity and reduce systematics at large angular scales, including the ability to measure beams in the far field with high precision. Finally, I will discuss the prospects for dealing with temperature-to-polarization leakage in future experiments, and how the beams systematics levels we achieve with current instrument and analysis technology will scale with detector count.
