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标题：Broadband study of blazar 1ES 1959+650 during flaring state in 2016
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作者：S. R. Patel ; A. Shukla ; V. R. Chitnis 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2018
卷号：611
DOI：10.1051/0004-6361/201731987
语种：English
出版社：EDP Sciences
摘要：Aims.The nearby TeV blazar 1ES 1959+650 (z= 0.047) was reported to be in flaring state during June–July 2016 byFermi-LAT, FACT, MAGIC and VERITAS collaborations. We studied the spectral energy distributions (SEDs) in different states of the flare during MJD 57530–57589 using simultaneous multiwaveband data with the aim of understanding the possible broadband emission scenario during the flare.Methods.The UV-optical and X-ray data from UVOT and XRT respectively on boardSwiftand high energyγ-ray data fromFermi-LAT were used to generate multiwaveband lightcurves as well as to obtain high flux states and quiescent state SEDs. The correlation and lag between different energy bands was quantified using discrete correlation function. The synchrotron self-Compton (SSC) model was used to reproduce the observed SEDs during flaring and quiescent states of the source.Results.A good correlation is seen between X-ray and high energyγ-ray fluxes. The spectral hardening with increase in the flux is seen in X-ray band. The power law index vs. flux plot inγ-ray band indicates the different emission regions for 0.1–3 GeV and 3–300 GeV energy photons. Two zone SSC model satisfactorily fits the observed broadband SEDs. The inner zone is mainly responsible for producing synchrotron peak and high energyγ-ray part of the SED in all states. The second zone is mainly required to produce less variable optical-UV and low energyγ-ray emission.Conclusions.Conventional single zone SSC model does not satisfactorily explain broadband emission during observation period considered. There is an indication of two emission zones in the jet which are responsible for producing broadband emission from optical to high energyγ-rays.
关键词：Key wordsenradiation mechanisms: non-thermalBL Lacertae objects: individual: 1ES 1959+650gamma rays: generalX-rays: galaxies