Using millimeter-very long baseline interferometry (VLBI) observations of the BL Lac object S5 0716+714 from August 2008 to September 2013, we investigate variations in the core flux density and orientation of the sub-parsec scale jet i.e. position angle. The gamma-ray data obtained by the Fermi-LAT (Large Area Telescope) are used to investigate the high-energy flux variations over the same time period. For the first time in any blazar, we report a significant correlation between the gamma-ray flux variations and the position angle (PA) variations in the VLBI jet. The cross-correlation analysis also indicates a positive correlation such that the mm-VLBI core flux density variations are delayed with respect to the gamma-ray flux by 82±32 days. This suggests that the high-energy emission is coming from a region located ≥(3.8±1.9) parsecs upstream of the mm-VLBI core (closer to the central black hole). These results imply that the observed inner jet morphology has a strong connection with the observed gamma-ray flares.
@article{arxiv.1410.0196,
title = {Jet outflow and gamma-ray emission correlations in S5 0716+714},
author = {B. Rani and T. P. Krichbaum and A. P. Marscher and S. G. Jorstad and J. A. Hodgson and L. Fuhrmann and J. A. Zensus},
journal= {arXiv preprint arXiv:1410.0196},
year = {2014}
}
Comments
5 pages, 6 figures, accepted for publication in A&A Letters