The connection between the parsec-scale radio jet and γ-ray flares in the blazar 1156+295

Abstract

The blazar 1156+295 was active at γ-ray energies, exhibiting three prominent flares during the year 2010. Here, we present results using the combination of broad-band (X-ray through mm single-dish) monitoring data and radio-band imaging data at 43 GHz on the connection of γ-ray events to the ejections of superluminal components and other changes in the jet of 1156+295. The kinematics of the jet over the interval 2007.0-2012.5 using 43 GHz Very Long Baseline Array observations reveal the presence of four moving and one stationary component in the inner region of the blazar jet. The propagation of the third and fourth components in the jet corresponds closely in time to the active phase of the source in γ-rays. We briefly discuss the implications of the structural changes in the jet for the mechanism of γ-ray production during bright flares. To localize the γ-ray emission site in the blazar, we performed the correlation analysis between the 43 GHz radio core and the γ-ray light curve. The time lag obtained from the correlation constrains the γ-ray emitting region in the parsec-scale jet.