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dc.contributor.authorLang, Marken
dc.contributor.authorGillanders, Garyen
dc.identifier.citationThe VERITAS Collaboration: V. A. Acciari, E. Aliu, M. Beilicke, W. Benbow, D. ...(2010)Discovery of Variability in the Very High Energy Gamma-Ray Emission of 1ES 1218+304 with VERITAS. Astrophysical Journal Letters 709 (2010) L163-L167en
dc.description.abstractWe present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ~6% of the Crab Nebula flux, the new VERITAS data reveal a prominent flare reaching ~20% of the Crab. While very high energy (VHE) flares are quite common in many nearby blazars, the case of 1ES 1218+304 (redshift z = 0.182) is particularly interesting since it belongs to a group of blazars that exhibit unusually hard VHE spectra considering their redshifts. When correcting the measured spectra for absorption by the extragalactic background light, 1ES 1218+304 and a number of other blazars are found to have differential photon indices less than 1.5. The difficulty in modeling these hard spectral energy distributions in blazar jets has led to a range of theoretical gamma-ray emission scenarios, one of which is strongly constrained by these new VERITAS observations. We consider the implications of the observed light curve of 1ES 1218+304, which shows day scale flux variations, for shock acceleration scenarios in relativistic jets, and in particular for the viability of kiloparsec-scale jet emission scenarios.en
dc.rightsAttribution-NonCommercial-NoDerivs 3.0 Ireland
dc.subjectAstrophysics - High Energy Astrophysical Phenomenaen
dc.subjectAstrophysics - Cosmology and Extragalactic Astrophysicsen
dc.titleDiscovery of Variability in the Very High Energy Gamma-Ray Emission of 1ES 1218+304 with VERITASen
dc.local.authorsThe VERITAS Collaboration: V. A. Acciari, E. Aliu, M. Beilicke, W. Benbow, D. Boltuch, M. B\"ottcher, S. M. Bradbury, V. Bugaev, K. Byrum, A. Cesarini, L. Ciupik, P. Cogan, W. Cui, R. Dickherber, C. Duke, A. Falcone, J. P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, K. Gibbs, R. Guenette, G. H. Gillanders, S. Godambe, J. Grube, D. Hanna, C. M. Hui, T. B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, H. Krawczynski, F. Krennrich, M. J. Lang, S. LeBohec, G. Maier, S. McArthur, A. McCann, P. Moriarty, T. Nagai, R. A. Ong, A. N. Otte, D. Pandel, J. S. Perkins, A. Pichel, M. Pohl, J. Quinn, K. Ragan, L. C. Reyes, P. T. Reynolds, E. Roache, H. J. Rose, M. Schroedter, G. H. Sembroski, A. W. Smith, D. Steele, S. P. Swordy, M. Theiling, S. Thibadeau, V. V. Vassiliev, S. Vincent, S. P. Wakely, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williamsen

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Attribution-NonCommercial-NoDerivs 3.0 Ireland
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