Self-calibration techniques in radio-astronomy

Abstract

Self-calibration is a technique used widely in radio-interferometry for high quality imaging of complex objects in conditions where the coherence samples are corrupted by severe amplitude and phase errors. It relies upon the concept of closure phase introduced by Roger Jennison in 1958. The closure phase is an observable which is unaffected by antenna-based calibration errors. However, rather than using the closure phases directly, the simplest form of self-calibration proceeds by allowing these antenna-based errors to be determined in the imaging process. This general principle is considerably more flexible than closure phase and can be extended to many different applications.