Radio variability of the gamma - ray blazar 0202 + 149
نویسنده
چکیده
Analysis of radio light curves of the γ-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 ∼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 (r ≤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.
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