Rapid radio variations in the flux density of BL Lacertae

• Published in: The Astrophysical journal Vol. 277; no. 2; pp. L31 - L34
• Main Authors: JOHNSTON, K. J, GELDZAHLER, B. J, SPENCER, J. H, WALTMAN, E. B, KLEPCZYNSKI, W. J, JOSTIES, F. J, ANGERHOFER, P. E, FLORKOWSKI, D. R, MCCARTHY, D. D, MATSAKIS, D. N
• Format: Journal Article
• Language: English
• Published: Chicago, IL University of Chicago Press 15.02.1984
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Radio sources; Stellar systems. Galactic and extragalactic objects and systems. The universe; Unidentified sources and radiation outside the solar system; BL Lac object radiosource; Flux density; Radio observation; Variability
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/184196

The flux density of BL Lac has been monitored daily at 11.1 and 3.7 cm from 1979 January through 1982 June (JD 2,443,875-JD 2,445,150). During this period, the flux density varied from 2 to 14 Jy at 2.7 cm, and although significant variations were found over time intervals of days, the flux density was dominated by outbursts which had a time scale of approximately 100 days. The variations are consistent with repeated injections of relativistic particles and subsequent decay by a single source. During the period 1980.0 to 1981.2, there were at least ten major injections of relativistic particles, making it very difficult to trace the evolution of individual events during this period by high-resolution (milli-arcsec) maps of BL Lac unless the maps were sampled at 25 day intervals. After 1981.5, only one additional major injection occurred; thus, high-resolution maps separated in time by several months may be able to trace the evolution of this event unambiguously.