2001/02/26 by Svetlana G. Jorstad, Alan P. Marscher, John R. Mattox +4 · 3 citations
Earth and Planetary Sciences · Physics and Astronomy · #Active galactic nucleus #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Blazar #Earth Systems and Cosmic Evolution #Egret #Flare #Quasar #Relativistic beaming #Superluminal motion #Very Long Baseline Array #Very-long-baseline interferometry #astro-ph
paper · pdf · doi:10.1086/321605
23 pages, 3 tables, 5 figures, submitted to ApJ
arxiv created 2001/02/26 · openalex publication_date 2001/08/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We examine the coincidence of times of high γ-ray flux and ejections of superluminal components from the core in EGRET blazars based on a Very Long Baseline Array (VLBA) monitoring program at 22 and 43 GHz from 1993 November to 1997 July. In 23 cases of γ-ray flares for which sufficient VLBA data exist, 10 of the flares (in eight objects) fall within 1 σ uncertainties of the extrapolated epoch of zero separation from the core of a superluminal radio component. In each of two sources (0528+134 and 1730-130), two successive γ-ray flares were followed by the appearance of new superluminal components. We carried out statistical simulations that show that if the number of coincidences is ≥10, the radio and γ-ray events are associated with each other at greater than 99.999% confidence. Our analysis of the observed behavior, including variability of the polarized radio flux, of the sources before, during, and after the γ-ray flares suggests that the γ-ray events occur in the superluminal radio knots. This implies that the γ-ray flares are caused by inverse Compton scattering by relativistic electrons in the parsec-scale regions of the jet rather than closer to the central engine.