Speaker
Description
Calibration approaches for 21 cm cosmology experiments can be broadly categorized as either ‘sky-based,’ relying on an extremely accurate model of astronomical foreground emission, or ‘redundant,’ requiring a precisely regular array with near-identical antenna response patterns. We show that sky-based and redundant calibration can be unified into a highly general and physically motivated calibration framework based on a Bayesian statistical formalism. This novel calibration framework relaxes the rigid assumptions implicit in each sky-based and redundant calibration. It can account for sky model incompleteness, antenna position offsets, and beam response inhomogeneities. Furthermore, it enables new calibration techniques such as redundant calibration of arrays with no redundant baselines, such as the MWA Phase I. These new techniques could mitigate systematics and reduce calibration error, thereby improving the precision of cosmological measurements.
