VLBI and single-dish monitoring of 3C 84 for the period 2009-2011.

ABSTRACT The radio galaxy 3C 84 is a representative of γ-ray-bright misaligned active galactic nuclei (AGNs) and one of the best laboratories to study the radio properties of the subparsec jet in connection with the γ-ray emission. In order to identify possible radio counterparts of γ-ray emissions in 3C 84, we study the change in structure within the central 1 pc and the light curve of subparsec-sized components C1, C2 and C3. We search for any correlation between changes in the radio components and the γ-ray flares by making use of the Very Long Baseline Interferometry (VLBI) and single-dish data. Throughout the radio monitoring spanning over two GeV γ-ray flares detected by the Fermi Large Area Telescope and the MAGIC Cherenkov Telescope during 2009 April-May and 2010 June-August, the total flux density in the radio band increases on average. This flux increase mostly originates in C3. Although γ-ray flares span the time-scale of days to weeks, no clear correlation with the radio light curve on this time-scale is found. No new prominent components and change in morphology associated with the γ-ray flares are found on VLBI images. [ABSTRACT FROM AUTHOR]