Abstract
Long-term measurements of the radio flux density of Cassiopeia A relative to Cygnus A have been carried out at 927, 290, 151.5, and 38 MHz. The mean secular decreases in the radio flux of Cas A are d927 = -(0.73±0.05)% year-1 (for the period 1977.8-1996.8), d290 = -(0.66 ± 0.07)% year-1 (1978.8-1996.85), and d151.5 = -(1.11 ± 0.22)% year-1 (1980.9-1994.8). Using also the results of other studies, d38 = -(.66 ± 0.17)% year-1 (1956-1995.6) and d151.5 = -(.86 ± 0.09)% year-1 (1966.5-1994.8). The temporal nonuniformity of the Cas A flux density decrease is most likely due to random changes in the integrated radio emission of the approximately 300 compact features observed in this source.
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Adgie R. & Smith F.G.: 1956, Observatory 76, 181
Anderson M.C. & Rudnik L.: 1995, ApJ 441, 307
Ashwoth W.B.: 1980, J. Hist. Astron. 11, 1
Bazelyan L.L., Braude S.Ya., Bruk Yu.M. et al.: 1963, Izv. vuzov. Ser. Radiofizika 6, 897
Bell A.R.: 1977, MNRAS 179, 573
Braude S.Ya., Lebedeva O.M., Megn A.V. et al.: 1969, MNRAS 143, 301
Caswell J.L. & Lerch I.: 1979, Proc. Astron. Soc. Austral. 3, 343
Erickson W.C. & Perley R.A.: 1975, ApJ 200, L83
Fesen R.A., Becker R.H. & Goodrich R.W.: 1988, ApJ 329, L8
Kamper K. & van den Berg S.: 1976, ApJ Suppl. 32, 351
Lozinskaya T.A.: 1986, Sverkhnovye zvezdy i zvezdnyi veter. Vzaimodeistvie s gazom Galaktiki, Nauka: Moscow, 304
Parker E.A.: 1968, MNRAS 138, 407
Read P.L.: 1977a, MNRAS 178, 259
Read P.L.: 1977b, MNRAS 181, 63
Reed J.E., Hester J.J., Fabian A.C. & Winkler P.F.: 1995, ApJ 440, 706
Rees N.: 1990, MNRAS 243, 637
Shklovsky I.S.: 1960, Astron. Zh. 37, 256
Shklovsky I.S.: 1976a, Sverkhnovye zvezdy, Nauka: Moscow, 256
Shklovsky I.S.: 1976b, Pis'ma v Astr. Zh. 2, 244
Tuffs, R.J.: 1986, MNRAS 219, 13
Vinyajkin E.N., Volodin A.G. & Koval'chuk O.M.: 1992, Pis'ma v Astr. Zh. 18, 755
Vinyaikin E.N.: 1997, Ap.Tr. (in press)
Walczowski L.T. & Smith K.L.: 1985, MNRAS 212, 27
Whitfield G.R.: 1960, MNRAS 120, 581
Williams P.J.S., Kenderdine S. & Baldwin J.E.: 1966, Mem. RAS 70, 53
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Vinyajkin, E. Secular Decrease and Random Variations of the Flux Density of Cas a at 927, 290, 151.5, and 38 MHZ from Long-Term Measurements. Astrophysics and Space Science 252, 249–257 (1997). https://doi.org/10.1023/A:1000875931380
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DOI: https://doi.org/10.1023/A:1000875931380