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Browsing by Author "Barnacka, A."

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    EXCEPTIONALLY BRIGHT TEV FLARES FROM THE BINARY LS I+61 degrees 303
    (IOP Publishing, 2016-01-19) Archambault, S.; Archer, A.; Aune, T.; Barnacka, A.; Benbow, W.; Bird, R.; Buchovecky, M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cardenzana, J. V.; Cerruti, M.; Chen, X.; Ciupik, L.; Collins-Hughes, E.; Connolly, M. P.; Cui, W.; Dickinson, H. J.; Dumm, J.; Eisch, J. D.; Falcone, A.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Flinders, A.; Fortin, P.; Fortson, L.; Furniss, A.; Gillanders, G. H.; Griffin, S.; Grube, J.; Gyuk, G.; Huetten, M.; Hakansson, N.; Hanna, D.; Holder, J.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krause, M.; Krennrich, F.; Kumar, S.; Lang, M. J.; Maier, G.; McArthur, S.; McCann, A.; Meagher, K.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nieto, D.; O'Brien, S.; de Bhroithe, A. O'Faolain; Ong, R. A.; Otte, A. N.; Pandel, D.; Park, N.; Pelassa, V.; Pohl, M.; Popkow, A.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Rousselle, J.; Rulten, C.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Vincent, S.; Wakely, S. P.; Weiner, O. M.; Weinstein, A.; Wilhelm, A.; Williams, D. A.; Zitzer, B.; McGill University; Washington University (WUSTL); University of California System; University of California Los Angeles; Harvard University; Smithsonian Astrophysical Observatory; Smithsonian Institution; University College Dublin; United States Department of Energy (DOE); Argonne National Laboratory; Iowa State University; University of Potsdam; Helmholtz Association; Deutsches Elektronen-Synchrotron (DESY); Ollscoil na Gaillimhe-University of Galway; Purdue University System; Purdue University; Purdue University West Lafayette Campus; University of Minnesota System; University of Minnesota Twin Cities; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; Utah System of Higher Education; University of Utah; California State University System; California State University East Bay; University of Delaware; Columbia University; University of California Santa Cruz; University of Iowa; DePauw University; University System of Georgia; Georgia Institute of Technology; Grand Valley State University; University of Chicago; Cork Institute of Technology; National Aeronautics & Space Administration (NASA); NASA Goddard Space Flight Center; University System of Maryland; University of Maryland College Park; University of Alabama Tuscaloosa
    The TeV binary system LS I +61 degrees 303 is known for its regular, non-thermal emission pattern that traces the orbital period of the compact object in its 26.5 day orbit around its B0 Ve star companion. The system typically presents elevated TeV emission around apastron passage with flux levels between 5% and 15% of the steady flux from the Crab Nebula (> 300 GeV). In this article, VERITAS observations of LS I + 61 degrees. 303 taken in late 2014 are presented, during which bright TeV flares around apastron at flux levels peaking above 30% of the Crab Nebula flux were detected. This is the brightest such activity from this source ever seen in the TeV regime. The strong outbursts have rise and fall times of less than a day. The short timescale of the flares, in conjunction with the observation of 10 TeV photons from LS I + 61 degrees 303 during the flares, provides constraints on the properties of the accelerator in the source.
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    A SEARCH FOR PULSATIONS FROM GEMINGA ABOVE 100 GeV WITH VERITAS
    (IOP Publishing, 2015-02-09) Aliu, E.; Archambault, S.; Archer, A.; Aune, T.; Barnacka, A.; Beilicke, M.; Benbow, W.; Bird, R.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cardenzana, J. V.; Cerruti, M.; Chen, X.; Ciupik, L.; Connolly, M. P.; Cui, W.; Dickinson, H. J.; Dumm, J.; Eisch, J. D.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Fortin, P.; Fortson, L.; Furniss, A.; Gillanders, G. H.; Griffin, S.; Griffiths, S. T.; Grube, J.; Gyuk, G.; Kansson, N. H. A.; Hanna, D.; Holder, J.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kertzman, M.; Kieda, D.; Krennrich, F.; Kumar, S.; Lang, M. J.; Lyutikov, M.; Madhavan, A. S.; Maier, G.; McArthur, S.; McCann, A.; Meagher, K.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nieto, D.; de Bhroithe, A. O'Faolain; Ong, R. A.; Otte, A. N.; Park, N.; Pohl, M.; Popkow, A.; Prokoph, H.; Pueschel, E.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Varlotta, A.; Vincent, S.; Wakely, S. P.; Weinstein, A.; Williams, D. A.; Zajczyk, A.; Zitzer, B.; Columbia University; Institut d'Estudis Espacials de Catalunya (IEEC); University of Barcelona; McGill University; Washington University (WUSTL); University of California System; University of California Los Angeles; Harvard University; Smithsonian Astrophysical Observatory; Smithsonian Institution; University College Dublin; United States Department of Energy (DOE); Argonne National Laboratory; Iowa State University; University of Potsdam; Helmholtz Association; Deutsches Elektronen-Synchrotron (DESY); Ollscoil na Gaillimhe-University of Galway; Purdue University System; Purdue University; Purdue University West Lafayette Campus; University of Minnesota System; University of Minnesota Twin Cities; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; University of California Santa Cruz; University of Iowa; University of Delaware; Utah System of Higher Education; University of Utah; DePauw University; University of Chicago; University System of Georgia; Georgia Institute of Technology; California State University System; California Polytechnic State University San Luis Obispo; Cork Institute of Technology; University of Alabama Tuscaloosa
    We present the results of 71.6 hr of observations of the Geminga pulsar (PSR J0633+1746) with the VERITAS very-high-energy gamma-ray telescope array. Data taken with VERITAS between 2007 November and 2013 February were phase-folded using a Geminga pulsar timing solution derived from data recorded by the XMM-Newton and Fermi-LAT space telescopes. No significant pulsed emission above 100 GeV is observed, and we report upper limits at the 95% confidence level on the integral flux above 135 GeV (spectral analysis threshold) of 4.0x10(-13) s(-1) cm(-2) and 1.7 x 10(-13) s(-1) cm(-2) for the two principal peaks in the emission profile. These upper limits, placed in context with phase-resolved spectral energy distributions determined from 5 yr of data from the Fermi-Large Area Telescope (LAT), constrain possible hardening of the Geminga pulsar emission spectra above similar to 50 GeV.