Monitoring of 3C 66A during an extended outburst. I. The light curves^*

¹ Tuorla Observatory, FIN-21500 Piikkiö, Finland
² Instituto de Astrofísica de Canarias, La Laguna, 38200 Tenerife, Spain
³ 1655 Main St. Stittsville, Ont. K2S 1N6, Canada
⁴ Instituto de Astronomía-UNAM, Apdo. Postal 70-264, 04510, Mexico, D.F. Mexico
⁵ Department of Astronomy, Indiana University, Swain West 319, Bloomington, IN 47405, U.S.A.
⁶ Crimean Astrophysical Observatory, P/O Nauchny, 334413 Crimea, Ukraine
⁷ University of Oxford, Dept. of Astrophysics, Nuclear & Astrophysics Laboratory, Keble Road Oxford, OX1 3RH, UK
⁸ Hamburger Sternwarte, Hamburg Universität, Gojensbergweg 112, D-21029 Hamburg 80, Germany
⁹ Bradley Observatory, Agnes Scott College, Decatur, GA 30030, U.S.A.
¹⁰ Capilla Peak Observatory, University of New Mexico, Albuquerque, NM 87131, U.S.A.
¹¹ Landessternwarte Königstuhl, D-69117 Heidelberg, Germany
¹² Osservatorio Astronomico, Universitá di Perugia, I-601123 Perugia, Italy
¹³ Osservatorio Astronomico di Torino, Strada Osservatorio 20, I-10025, Pino Torinese, Italy
¹⁴ The Astronomer Organization, Birmingham, England
¹⁵ University of Michigan, Ann Arbor, MI, U.S.A.
¹⁶ Metsähovi Radio Research Station, Kylmälä, Finland

Send offprint request to: L.O. Takalo

Received: 15 April 1996
Accepted: 22 April 1996

Abstract

We present results from a two year intensive monitoring of BL Lac object 3C 66A (PKS 0219+428). This object was observed in outburst during these two years. It reached the brightest ever observed magnitude on V=13.59 (1.2.1995) and on K=10.59 (15.2.1994). The optical and infrared light curves are characterised by randomly distributed fast flares, lasting a few days and well defined outbursts lasting a week or two. On top of these flares we can occasionally see small amplitude microvariability. No clear correlation can be found between the spectral behaviour and the occurrence of these flares. In the radio bands 3C 66A was quite faint and very stable compared to the optical variations. The light curves will be presented with preliminary analysis and discussions on the possible causes for the observed variations.