Quasi-simultaneous radio spectrum from RATAN-600 (2–22 GHz; the data in all bands was taken simultaneously on MJD 57631.8) and SMA (230 GHz; the data was taken on MJD 57631.2). The data point for the SMA is an average over the 1.5 hour exposure and the error bars indicate the standard deviation of the measurements during the exposure. The spectrum is fitted with several models (SSA: synchroton self-absorption, FFA: free-free absorption, RT: Razin-Tsytovitch effect). See text for more details.