A new approach to multifrequency synthesis in radio interferometry

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.