SECULAR DECREASE THE FLUX OF SUPERNOVA REMNANT CAS A ON MONITORING RESULTS TO RADIOTELESCOPE "URAN-4" IRA NASU

Анотація

This work is dedicated to the study of secular decrease of the flux of young supernova remnant Cas A according to observations by radio- telescope "URAN-4» of Odessa Observatory IRA NASU from 1987 to 2001 years on frequency of 25 MHz. On the investigation base there is a relationship analysis of flux CasA to the "stable" source – radio-galaxy Cyg A (CasA/Cyg A) which is located on a small angular distance. Results of the observations held on RT «URAN- 4» show that there is no noticeable decrease of fluxes in the period 1987-1993, with the relationship ratio (CasA/Cyg A) = 1.5. While considering data from 1987 to 2001 manifested a slight decrease trend in flux equal to 8.4% for the all period. At the same time, according to various investigations the average value flux of Cas A in the interval of frequencies 38-2924 MHz is 0.8% per year. At the meantime in this frequency the range ratio (CasA/Cyg A) has become less than one. Thus, there is a noticable contradiction of secular decrease of the flux Cas A on this radio frequencies in comparison with the predictions of the theory in 1.7% per year.