Study On Extreme Gamma-ray Outburst In Blazars And The Tidal Disruption Events

Blazar is one of the most active objects in the universe.Current observations show that there are a class of extreme gamma-ray outbursts with extremely short timescales and extremely high peak flux in blazars'outbursts.The origin of the extreme outbursts is not yet determined.Tidal disruption event(TDE)is also a kind of extreme outburst phenomenon.When a star is captured by a black hole,due to the black hole tidal force,the star could be torn,resulting in the TDE.For blazars,because the mass of the central supermassive black hole is generally about 10~8_?or higher,for a sun-type star,the tidal collapse radius is within the gravitational radius of the black hole.Consequently,the star will be swallowed directly by the central supermassive black hole,and no TDE happens.However,considering that blazar system consists of a black hole,an accretion disk and a relativistic jet,and gamma-rays are generated in the jet.Using the physical scenario of TDE,we wonder whether the interaction between a star and the jet can produce extreme gamma ray outbursts?In our study,we find that a jet-red giant interaction model has been proposed for some outbursts in active galactic nuclei.The model is very similar to our guess.Therefore,in this thesis,we first investigate the jet-red giant interaction model,and study the energy budget and dynamic timescales.Then,we process the Fermi-LAT data of the flat spectrum radio quasar 3C 279 in the last 10years.For the extreme gamma-ray outburst in June 2015,the hour and minute timescales sampled light curves are constructed.It is found that the jet-red giant interaction model can explain this extreme gamma-ray outburst of 3C 279 from the aspect variability timescale and energy budget.This conclusion can be tested with the characteristics of the gamma-ray light curves,we will carry out this test in the future.