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Astron. Astrophys. 358, 451-461 (2000)


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Radio variability of the gamma-ray blazar 0202+149

T.B. Pyatunina 1, S.G. Marchenko 2,3, A.P. Marscher 3, M.F. Aller 4, H.D. Aller 4, H. Teräsranta 5 and E. Valtaoja 6

1 Institute of Applied Astronomy, Zhdanovskaya St. 8, 197110 St. Petersburg, Russia (ptb@ipa.rssi.ru)
2 Astronomical Insitute, St. Petersburg State University, Bibliotechnaya pl. 2, 198904 St. Petersburg, Russia
3 Institute for Astrophysical Research, Boston University, 725 Commonwealth Ave., Boston, MA 02215, USA
4 Astronomy Department, University of Michigan, Ann Arbor, MI 48109, USA
5 Metsähovi Radio Research Station, Helsinki University of Technology, 02540 Kylmälä, Finland
6 Tuorla Observatory, University of Turku, 21500 Piikkiö, Finland

Received 23 April 1999 / Accepted 11 February 2000

Abstract

Analysis of radio light curves of the [FORMULA]-ray bright blazar 0202+149 at frequencies of 37, 22, 14.5, 8, and 4.8 GHz during the period 1984-1998 reveals a 4-year cycle of variability with substructure on a shorter time scale of about 1.3-yr. The 4.8-37 GHz spectral index of the source gradually increases from -0.04 (T=1990.2) to 0.4 (T=1996.6) and during outbursts shows strong variations with a time scale of about 1 year and an amplitude up to [FORMULA]0.4. VLBI images at 8, 22, and 43 GHz show a core-dominated structure with a faint jet in the northwest direction, which we trace out to 7 mas, with a bent inner part ([FORMULA]1 mas) consisting of at least 2 components. The connection of the jet activity with the 4-year cycle of total flux density variability is discussed.

Key words: galaxies: active – galaxies: quasars: individual: 0202+149 – radio continuum: galaxies

Send offprint requests to: T.B. Pyatunina

© European Southern Observatory (ESO) 2000

Online publication: June 8, 2000

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