A new approach to multifrequency synthesis in radio interferometry

¹ Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
e-mail: henrikju@astro.uni-bonn.de
² Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany

Received: 19 January 2014
Accepted: 18 February 2015

Abstract

We present a new approach to multifrequency synthesis in radio astronomy. Using Bayesian inference techniques, the new technique estimates the sky brightness and the spectral index simultaneously. In principle, the bandwidth of a wide-band observation can be fully exploited for sensitivity and resolution, currently only limited by higher order effects like spectral curvature. Employing this new approach, we further present a multifrequency extension to the imaging algorithm resolve. This method also delivers a reconstruction of the most probable spectral index spatial correlation structure across the source and an estimate of the spectral index uncertainty, although at a comparably high computational cost. In simulations, this new algorithm can outperform current multifrequency imaging techniques.