Temporal variability and estimation of jet parameters for Ton 599


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The TeV blazar Ton 599 has exhibited a peculiar flare in 2017 November. The temporal variation of the source is studied using simultaneous $gamma$-ray data from $textit{Fermi}$ Large Area Telescope and radio data from Owens Valley Radio Observatorys 40 m telescope, over the period of nine years. Four major flaring periods are observed in the $gamma$-ray energy band of 0.1-300 GeV. These periods are studied on a shorter timescale and modeled with a time-dependent function containing exponential rising and decaying components. The physical parameters of the jet are estimated numerically and compared with those reported in the literature. During the fourth flare a bunch of high energy photons ($>$10 GeV) were detected. The two highest energy photons having an energy of 76.9 GeV and 61.9 GeV are detected on MJD 58059.0 and 58073.3, respectively. This observation possibly constrains the $gamma$-ray emission region to lie near outer edge or outside the broad line region of size $sim$0.08 pc. The variation of equivalent width of a Mg-II line is studied using the spectroscopic data from Steward observatory. It was observed that the equivalent width of the line varies inversely with the underlying power-law continuum.

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