Abstract Details
| Name: Kiran S Baliyan Affiliation: Physical Research Laboratory, Ahmedabad Conference ID: ASI2015_527 Title : Signature of the precession of relativistic jet in blazars Authors and Co-Authors : Sunil Chandra*, Navpreet Kaur, S Ganesh, K S Baliyan Physical Research Laboratory, Ahmedabad *Now at TIFR, Mumbai. Abstract Type : Poster Abstract Category : Extragalactic astronomy Abstract : The matter accretes on the black hole through the disc powering the relativistic jet, which dominates the emission at all wavelengths in blazars. The exact mechanisms responsible for the origin, acceleration and collimation of the jet are not well understood. Since central engine is not resolvable by any existing optical facility, variability in flux can be used as a tool to understand the structure and physical processes in the jet. Blazars show variability in their flux at all frequencies with time scales ranging from years to minutes and appear good candidates for such study. The physical processes responsible for such variations provide important clues to the nature of the jet and emissions from it. Long duration monitoring of blazars is expected to throw light on the long-term variability patterns of the source, which, in case of blazars, are imprints of the jet structure and dynamics. We have used long-term monitoring data from Mt Abu Observatory to construct light-curves for blazar S5 0716+714. The light-curve show that during 2005- 2012, source brightness decreased while it increased during 1996-2003. It was accompanied with decrease in viewing angle (angle between jet direction and the line of sight) from about 5 degree to about 2.0 degree during 1996-2003 and then increasing trend during 2003 – 2012 as determined from VLBI images. A decrease in viewing angle leads to enhancement of brightness. Available historical light-curves show a brightness decreasing trend during 1963 – 1981 and a fast increasing one during 1988-1995. This average brightness behaviour is superposed with slow flares and faster variations. Such long-term change in the brightness of the source associated with systematic variation in the viewing anlge indicates to precession of the relativistic jet on its axis. According to this, the average brightness of the source should start increasing sometime in 2015. Using our data and data from literature, we will discuss longterm behaviour of this blazar in the meeting. |