Researchers present first results of solar observations with the Siberian Radioheliograph
Russian scientists have presented the first results of solar observations made with the new radioheliograph of the Siberian Solar Radio Telescope (SSRT). The Siberian Radioheliograph (SRH), has just started regular observations of active processes in the sun’s atmosphere, which will facilitate better monitoring of solar activity. Results of the initial SRH observations were published in a paper published 25th April on arXiv.org.
SRH is a 48‑antenna array with a 4–8 GHz operating frequency range and a 10 MHz instantaneous receiving band. The instrument is installed on the SSRT telescope of the Radio Astrophysical Observatory (RAO), found in the Eastern Sayan Mountains, approximately 220 kilometers away from Irkutsk. Although the adjustment of the SRH system is still ongoing and the array is still incomplete, the first stage of this instrument has already provided promising preliminary results. SRH started single‑frequency test observations in early 2016, and since July 2016, it has consistently observed the sun at five frequencies. During this period, solar activity was low, which provided a wonderful opportunity to test the capabilities of this instrument.
During the initial observations, SRH recorded three negative bursts, which happened in one day. These bursts are temporary depressions of radio flux below the substitutionary level, triggered by a screening of emission from compact radio sources or quiet solar regions in low‑temperature plasma ejected into the solar corona. They are very rarely observed and provide essential information about eruptive events.
Overall, the preliminary observations provided satisfactory and promising results, proving that SRH enables the implementation of fast and effective algorithms for solar imaging without the need of reference observations of other cosmic sources. The SRH system will ultimately be expanded to 96 antennas, to improve its spatial resolution. This would enable the instrument to study processes of initiation of coronal mass ejections (CMEs) and their propagation up to heights of one to two solar radii, therefore filling the gap between observations in ultraviolet and optical ranges.