MULTIWAVELENGTH OBSERVATIONS AND MODELING OF 1ES 1959+650 IN A LOW FLUX STATE

作者：Aliu E^*; Archambault S; Arlen T; Aune T; Beilicke M; Benbow W; Bird R; Boettcher M; Bouvier A; Bugaev V; Byrum K; Cesarini A; Ciupik L; Collins Hughes E; Connolly M P; Cui W; Dickherber R; Duke C; Dumm J; Errando M; Falcone A; Federici S; Feng Q; Finley J P; Finnegan G; Fortson L; Furniss A; Galante N; Gall D; Gillanders G H; Griffin S; Grube J; Gyuk G; Hanna D; Holder J; Hughes G; Humensky T B; Kaaret P

来源：Astrophysical Journal, 2013, 775(1): 3.

DOI：10.1088/0004-637X/775/1/3

• BL Lacertae objects: general
• BL Lacertae objects: individual (1ES 1959+650=VER J1959+651)
• galaxies: active
• gamma rays: galaxies

We report on the VERITAS observations of the high-frequency peaked BL Lac object 1ES 1959+650 in the period 2007-2011. This source is detected at TeV energies by VERITAS at 16.4 standard deviation (sigma) significance in 7.6 hr of observation in a low flux state. A multiwavelength spectral energy distribution (SED) is constructed from contemporaneous data from VERITAS, Fermi-LAT, RXTE PCA, and Swift UVOT. Swift XRT data is not included in the SED due to a lack of simultaneous observations with VERITAS. In contrast to the orphan gamma-ray flare exhibited by this source in 2002, the X-ray flux of the source is found to vary by an order of magnitude, while other energy regimes exhibit less variable emission. A quasi-equilibrium synchrotron self-Compton model with an additional external radiation field is used to describe three SEDs corresponding to the lowest, highest, and average X-ray states. The variation in the X-ray spectrum is modeled by changing the electron injection spectral index, with minor adjustments of the kinetic luminosity in electrons. This scenario produces small-scale flux variability of the order of less than or similar to 2 in the high energy (E %26gt; 1MeV) and very high energy (E %26gt; 100 GeV) gamma-ray regimes, which is corroborated by the Fermi-LAT, VERITAS, and Whipple 10 m telescope light curves.

• 出版日期2013-9-20
• 单位西北大学