Fermi Gamma-ray Space Telescope

10 Years of VLBA-BU-BLAZAR Monitoring: Relationship between Gamma-ray and Millimeter-wave Events in Blazar Jets

Alan Marscher
(Svetlana G. Jorstad, Zachary R. Weaver, John M. Hunter, Karen E. Williamson, Katya A. Leidig)


Ten years of Fermi LAT gamma-ray observations and monthly VLBA imaging at 43 GHz reveal close connections between high-energy outbursts and activity seen in the millimeter-wave images. The timing of flares in the stationary `cores' and emergence of superluminal knots, relative to the onset and peak of gamma-ray outbursts, in many blazars allows us to locate the distance of the event from the black hole. Nearly every gamma-ray outburst has a 43 GHz counterpart, while more than half of new superluminal knots are unrelated to gamma-ray events. These results allow us to draw important inferences on the sources of seed photons for inverse Compton scattering and the particle acceleration processes that ignite multi-waveband outbursts. This research was supported in part by NASA Fermi Guest Investigator grant 80NSSC17K0649.