BICEP Array: a Next-Generation CMB Polarimeter to probe the primordial universe from the South Pole
The inflationary scenario generically predicts the existence of primordial gravitational waves (GW) over a wide range of amplitudes from slow-roll to multi-field models. Currently the most promising method for constraining, and potentially detecting an inflationary GW background is to search for the imprint of these tensor perturbations in the cosmic microwave background (CMB) B-mode polarization. With ever-increasing sensitivity at degree angular scales, the BICEP/Keck program targets these B-modes, producing the most stringent constraints on primordial inflation to date. BICEP Array, a “Stage 3” generation instrument, will begin observing at the South Pole in 2020. BICEP Array expands the frequency coverage of its predecessors with four receivers operating in six bands. The first receiver is currently being commissioned and will operate at 30-40GHz to constrain synchrotron foreground emission. In later years, 95 GHz and 150 GHz receivers will continue to deepen our maps of the CMB, while higher-frequency channels at 220/270GHz will provide unprecedented constraints on the galactic dust foreground. This talk will present an overview of the design and expected performance of the BICEP Array instruments. I will show predicted constraints on the synchrotron foreground provided by the first low-frequency receiver. I will also outline how BICEP Array will inform CMB ‘Stage 4’ experiments, in particular future Small Aperture Telescopes targeting signatures of inflation.