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Title: INVESTIGATING BROADBAND VARIABILITY OF THE TeV BLAZAR 1ES 1959+650

We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift Ultraviolet and Optical Telescope, X-ray observations by the Swift X-ray Telescope, high-energy gamma-ray observations with the Fermi Large Area Telescope, and very-high-energy (VHE) gamma-ray observations by VERITAS above 315 GeV, all taken between 2012 April 17 and 2012 June 1 (MJD 56034 and 56079). The contemporaneous variability of the broadband spectral energy distribution is explored in the context of a simple synchrotron self Compton (SSC) model. In the SSC emission scenario, we find that the parameters required to represent the high state are significantly different than those in the low state. Motivated by possible evidence of gas in the vicinity of the blazar, we also investigate a reflected emission model to describe the observed variability pattern. This model assumes that the non-thermal emission from the jet is reflected by a nearby cloud of gas, allowing the reflected emission to re-enter the blob and produce an elevated gamma-ray state with no simultaneous elevated synchrotron flux. The model applied here, although not required to explain the observed variability pattern, represents one possible scenario which can describe themore » observations. As applied to an elevated VHE state of 66% of the Crab Nebula flux, observed on a single night during the observation period, the reflected emission scenario does not support a purely leptonic non-thermal emission mechanism. The reflected emission model does, however, predict a reflected photon field with sufficient energy to enable elevated gamma-ray emission via pion production with protons of energies between 10 and 100 TeV.« less
Authors:
 [1] ;  [2] ; ;  [3] ;  [4] ; ; ;  [5] ; ;  [6] ;  [7] ; ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13] ;  [14] ;  [15] more »; ; « less
  1. Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States)
  2. Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada)
  3. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
  4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  5. Department of Physics, Washington University, St. Louis, MO 63130 (United States)
  6. Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States)
  7. Department of Physics and Astronomy and the Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States)
  8. School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)
  9. Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States)
  10. Institute of Physics and Astronomy, University of Potsdam, D-14476 Potsdam-Golm (Germany)
  11. Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States)
  12. School of Physics, National University of Ireland Galway, University Road, Galway (Ireland)
  13. Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907 (United States)
  14. School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)
  15. Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)
Publication Date:
OSTI Identifier:
22364850
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 797; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BL LACERTAE OBJECTS; BLACK HOLES; COSMIC PHOTONS; COSMIC PIONS; CRAB NEBULA; ENERGY SPECTRA; GALAXIES; GAMMA RADIATION; GEV RANGE; JETS; PARTICLE PRODUCTION; PHOTON EMISSION; QUASARS; TELESCOPES; TEV RANGE; ULTRAVIOLET RADIATION; X RADIATION