Radio Flaring Activity of 3C 345 and its Connection to Gamma-ray
  Emission
  3C 345 is one of the archetypical active galactic nuclei, showing structural
and flux variability on parsec scales near a compact unresolved radio core.
During the last 2 years, the source has been undergoing a period of high
activity visible in the broad spectral range, from radio through high-energy
bands. We have been monitoring parsec-scale radio emission in 3C 345 during
this period at monthly intervals, using the VLBA at 15, 24, and 43 GHz. Our
radio observations are compared with gamma-ray emission detected by Fermi-LAT
in the region including 3C 345 (1FGL J1642.5+3947). Three distinct gamma-ray
events observed in this region are associated with the propagation of
relativistic plasma condensations inside the radio jet of 3C 345. We report on
evidence for the gamma-rays to be produced in a region of the jet of up to 40
pc (de-projected) in extent. This suggests the synchrotron self-Compton process
as the most likely mechanism for production of gamma-rays in the source.
