Spectrum Anomaly of the Supernova Remnant 3C58

Abstract

We measured the instantaneous spectra of the supernova remnant 3C58 for the epochs: 2003.4, 2004.4, and 2013.2 with the RTF-32 radio telescope of the “Svetloe” IAA RAS observatory at four frequencies from 1550 to 8450 MHz. The spectra of 3C58 for the time intervals: 1963–1971, 1981–1998, and 2004–2010 were obtained from the published data allowing us to compare the intensity of 3C58 and standard sources. To reduce all the data to a unified system and build the spectra, we used the “artificial moon” flux scale. Comparison of the spectra according to the data obtained in 1963–2013 revealed non-stationary frequency-dependent variations of flux densities, as well as local deviations of the 3C58 spectra from the frequency power law. Possible causes of the detected anomalies are discussed.