Evolution of Radio Emission of Cassiopeia A Supernova Remnant by Fifty Year Observations near to Frequencies 12.6, 14.7, 16.7, 20, and 25 MHz

V. P. Bovkoon, I. N. Bubnov, I. N. Zhouck, O. O. Konovalenko

Abstract


The results of measurements in the ratios of flux densities of Cas A supernova remnant and Cyg A radio galaxy in the time interval 1959.5– 2009.4 at frequencies 12.6, 14.7, 16.7, 20, and 25 MHz are shown. The radio telescopes used in these measurements are briefly mentioned. Strong variations in Cas A flux densities at decameter wavelengths are shown to be observed. The average drop rate of Cas A flux density for a 50-year period has been determined. For the decameters, it makes (0.81± 0.04) % a year, being frequency independent within the measuring errors.

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References


Бовкун В.П. Эволюция радиоизлучения остатка сверхновой Кассиопеи А по пятидесятилетним наблюдениям вблизи частот 12.6, 14.7, 16.7, 20 и 25 МГц / В.П. Бовкун, И.Н. Бубнов, И.Н. Жук, А.А. Коноваленко // Радиофизика и радиоастрономия. — 2010. — Т. 15, № 3. — С. 249-263.




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