Imaging of the Solar Atmosphere by the Siberian Solar Radio Telescope at 5.7 GHz with an Enhanced Dynamic Range

Abstract

Abstract The Siberian Solar Radio Telescope (SSRT) is a solar-dedicated directly-imaging interferometer observing the Sun at 5.7 GHz. SSRT has operated in the two-dimensional mode since 1996. The imaging principle of SSRT restricts its opportunities in observations of very bright flare sources, while it is possible to use ‘dirty’ images in studies of low-brightness features, which do not overlap with side lobes from bright sources. The interactive CLEAN technique routinely used for SSRT data provides imaging of active regions, but consumes much time and efforts and does not reveal low-brightness features below the CLEAN threshold. The newly developed technique combines the CLEAN routine with the directly-imaging capability of SSRT, and provides clean images with an enhanced dynamic range automatically. These elaborations considerably extend the range of tasks that can be solved with SSRT. We show here some examples of the present opportunities of SSRT, and compare its data with the images produced by the Nobeyama Radioheliograph at 17 GHz as well as observations in different spectral ranges.