A three-year multi-wavelength study of the very-high-energy γ-ray blazar 1es 0229+200

E. Aliu, S. Archambault, T. Arlen, T. Aune, B. Behera, M. Beilicke, W. Benbow, K. Berger, R. Bird, A. Bouvier, J. H. Buckley, V. Bugaev, K. Byrum, M. Cerruti, X. Chen, L. Ciupik, M. P. Connolly, W. Cui, C. Duke, J. DummM. Errando, A. Falcone, S. Federici, Q. Feng, J. P. Finley, H. Fleischhack, P. Fortin, L. Fortson, A. Furniss, N. Galante, G. H. Gillanders, S. Griffin, S. T. Griffiths, J. Grube, G. Gyuk, D. Hanna, J. Holder, G. Hughes, T. B. Humensky, C. A. Johnson, P. Kaaret, M. Kertzman, Y. Khassen, D. Kieda, H. Krawczynski, F. Krennrich, M. J. Lang, A. S. Madhavan, G. Maier, P. Majumdar, S. McArthur, A. McCann, K. Meagher, J. Millis, P. Moriarty, R. Mukherjee, D. Nieto, A. O'Faoláin De Bhróithe, R. A. Ong, A. N. Otte, N. Park, J. S. Perkins, M. Pohl, A. Popkow, H. Prokoph, J. Quinn, K. Ragan, L. C. Reyes, P. T. Reynolds, G. T. Richards, E. Roache, G. H. Sembroski, A. W. Smith, D. Staszak, I. Telezhinsky, M. Theiling, A. Varlotta, V. V. Vassiliev, S. Vincent, S. P. Wakely, T. C. Weekes, A. Weinstein, R. Welsing, D. A. Williams, A. Zajczyk, B. Zitzer

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The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Γ 2.5), very-high-energy (VHE; E > 100 GeV) emitting γ-ray blazar. VHE measurements of this active galactic nucleus have been used to place constraints on the intensity of the extragalactic background light and the intergalactic magnetic field (IGMF). A multi-wavelength study of this object centered around VHE observations by Very Energetic Radiation Imaging Telescope Array System (VERITAS) is presented. This study obtained, over a period of three years, an 11.7 standard deviation detection and an average integral flux F(E > 300 GeV) = (23.3 ± 2.8stat ± 5.8sys) × 10-9 photons m-2 s -1, or 1.7% of the Crab Nebula's flux (assuming the Crab Nebula spectrum measured by H.E.S.S). Supporting observations from Swift and RXTE are analyzed. The Swift observations are combined with previously published Fermi observations and the VHE measurements to produce an overall spectral energy distribution which is then modeled assuming one-zone synchrotron-self-Compton emission. The χ2 probability of the TeV flux being constant is 1.6%. This, when considered in combination with measured variability in the X-ray band, and the demonstrated variability of many TeV blazars, suggests that the use of blazars such as 1ES 0229+200 for IGMF studies may not be straightforward and challenges models that attribute hard TeV spectra to secondary γ-ray production along the line of sight.

Original languageEnglish (US)
Article number13
JournalAstrophysical Journal
Issue number1
StatePublished - Feb 10 2014

Bibliographical note

Funding Information:
Bristol, Myers, Squibb (SPAIN) supported partially the OpinAR and AfrontAR studies with patients. We thank all the doctors and patients belonging to the Spanish Patients? Forum and to Conartritis who have participated voluntarily in the surveys of the OpinAR and AfrontAR projects. We thank also to Bristol Myers Squibb, Spain, which funded both OpinAR and AfrontAR studies.

Funding Information:
S Castañeda has received trip aids for congresses and grants from Abbvie, Amgen, BMS, LILLY, MSD, Novartis, Pfizer, Roche, and UCB. Advisory Board consultation fees from Amgen, LILLY, MSD, Pfizer, Roche, and Sanofi. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.


  • BL Lacertae objects: general
  • diffuse radiation
  • galaxies: active
  • gamma rays: general
  • magnetic fields


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