Abstract
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 1MeV) and very high energy (E 100 GeV) gamma-ray regimes, which is corroborated by the Fermi-LAT, VERITAS, and Whipple 10 m telescope light curves.
| Original language | English (Ireland) |
|---|---|
| Journal | Astrophysical Journal |
| Volume | 775 |
| Publication status | Published - 1 Sep 2013 |
Authors (Note for portal: view the doc link for the full list of authors)
- Authors
- Aliu, E,Archambault, S,Arlen, T,Aune, T,Beilicke, M,Benbow, W,Bird, R,Bottcher, M,Bouvier, A,Bugaev, V,Byrum, K,Cesarini, A,Ciupik, L,Collins-Hughes, E,Connolly, MP,Cui, W,Dickherber, R,Duke, C,Dumm, J,Errando, M,Falcone, A,Federici, S,Feng, Q,Finley, JP,Finnegan, G,Fortson, L,Furniss, A,Galante, N,Gall, D,Gillanders, GH,Griffin, S,Grube, J,Gyuk, G,Hanna, D,Holder, J,Hughes, G,Humensky, TB,Kaaret, P,Kertzman, M,Khassen, Y,Kieda, D,Krawczynski, H,Krennrich, F,Lang, MJ,Madhavan, AS,Maier, G,Majumdar, P,McArthur, S,McCann, A,Moriarty, P,Mukherjee, R,Nelson, T,de Bhroithe, AO,Ong, RA,Orr, M,Otte, AN,Park, N,Perkins, JS,Pichel, A,Pohl, M,Popkow, A,Prokoph, H,Quinn, J,Ragan, K,Reyes, LC,Reynolds, PT,Roache, E,Saxon, DB,Schroedter, M,Sembroski, GH,Skole, C,Smith, AW,Staszak, D,Telezhinsky, I,The