@article{AliuArcherAuneetal.2015, author = {Aliu, E. and Archer, A. and Aune, T. and Barnacka, Anna and Behera, B. and Beilicke, M. and Benbow, W. and Berger, K. and Bird, R. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cardenzana, J. V. and Cerruti, M. and Chen, Xuhui and Ciupik, L. and Connolly, M. P. and Cui, Wei and Dickinson, H. J. and Dumm, J. and Eisch, J. D. and Errando, M. and Falcone, A. and Federici, Simone and Feng, Q. and Finley, J. P. and Fortin, P. and Fortson, L. and Furniss, A. and Galante, N. and Gillanders, G. H. and Griffin, S. and Griffiths, S. T. and Grube, J. and Gyuk, G. and Hakansson, Nils and Hanna, D. and Holder, J. and Hughes, G. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kar, P. and Kertzman, M. and Khassen, Y. and Kieda, D. and Krawczynski, H. and Krennrich, F. and Kumar, S. and Lang, M. J. and Madhavan, A. and McArthur, S. and McCann, A. and Meagher, K. and Millis, J. and Moriarty, P. and Nieto, Daniel and Ong, R. A. and Orr, M. and Otte, A. N. and Park, N. and Perkins, J. S. and Pohl, Martin and Popkow, A. and Prokoph, H. and Pueschel, Elisa and Quinn, J. and Ragan, K. and Rajotte, J. and Reyes, L. C. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Sembroski, G. H. and Shahinyan, K. and Staszak, D. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Varlotta, A. and Vassiliev, V. V. and Wakely, S. P. and Weinstein, A. and Welsing, R. and Wilhelm, Alina and Williams, D. A. and Zitzer, B.}, title = {Veritas observations of the BL LAC OBJECT PG 1553+113}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {799}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/799/1/7}, pages = {9}, year = {2015}, abstract = {We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560 GeV, is well described by a power law with a spectral index of 4.33 +/- 0.09. The time-averaged integral flux above 200 GeV measured for this period was (1.69 +/- 0.06) x 10(-11) photons cm(-2) s(-1), corresponding to 6.9\% of the Crab Nebula flux. We also present the combined gamma-ray spectrum from the Fermi Large Area Telescope and VERITAS covering an energy range from 100 MeV to 560 GeV. The data are well fit by a power law with an exponential cutoff at 101.9 +/- 3.2 GeV. The origin of the cutoff could be intrinsic to PG 1553+113 or be due to the gamma-ray opacity of our universe through pair production off the extragalactic background light (EBL). Given lower limits to the redshift of z > 0.395 based on optical/UV observations of PG 1553+113, the cutoff would be dominated by EBL absorption. Conversely, the small statistical uncertainties of the VERITAS energy spectrum have allowed us to provide a robust upper limit on the redshift of PG 1553+113 of z <= 0.62. A strongly elevated mean flux of (2.50 +/- 0.14) x10(-11) photons cm(-2) s(-1) (10.3\% of the Crab Nebula flux) was observed during 2012, with the daily flux reaching as high as (4.44 +/- 0.71) x10(-11) photons cm(-2) s(-1) (18.3\% of the Crab Nebula flux) on MJD 56048. The light curve measured during the 2012 observing season is marginally inconsistent with a steady flux, giving a chi(2) probability for a steady flux of 0.03\%.}, language = {en} } @article{AbeysekaraArcherBenbowetal.2018, author = {Abeysekara, A. U. and Archer, A. and Benbow, Wystan and Bird, Ralph and Brose, Robert and Buchovecky, M. and Buckley, J. H. and Bugaev, V. and Chromey, A. J. and Connolly, M. P. and Cui, Wei and Daniel, M. K. and Falcone, A. and Feng, Qi and Finley, John P. and Fortson, L. and Furniss, Amy and Huetten, M. and Hanna, David and Hervet, O. and Holder, J. and Hughes, G. and Humensky, T. B. and Johnson, Caitlin A. and Kaaret, Philip and Kar, P. and Kertzman, M. and Kieda, David and Krause, M. and Krennrich, F. and Kumar, S. and Lang, M. J. and Lin, T. T. Y. and McArthur, S. and Moriarty, P. and Mukherjee, Reshmi and Ong, R. A. and Otte, Adam Nepomuk and Park, Nahee and Petrashyk, A. and Pohl, Martin and Pueschel, Elisa and Quinn, J. and Ragan, K. and Reynolds, P. T. and Richards, Gregory T. and Roache, E. and Rulten, C. and Sadeh, I. and Santander, Marcos and Sembroski, G. H. and Shahinyan, Karlen and Sushch, I. and Tyler, J. and Wakely, S. P. and Weinstein, A. and Wells, R. M. and Wilcox, P. and Wilhelm, Alina and Williams, D. A. and Williamson, T. J. and Zitzer, B. and Abdollahi, S. and Ajello, Marco and Baldini, Luca and Barbiellini, G. and Bastieri, Denis and Bellazzini, Ronaldo and Berenji, B. and Bissaldi, Elisabetta and Blandford, R. D. and Bonino, R. and Bottacini, E. and Brandt, Terri J. and Bruel, P. and Buehler, R. and Cameron, R. A. and Caputo, R. and Caraveo, P. A. and Castro, D. and Cavazzuti, E. and Charles, Eric and Chiaro, G. and Ciprini, S. and Cohen-Tanugi, Johann and Costantin, D. and Cutini, S. and de Palma, F. and Di Lalla, N. and Di Mauro, M. and Di Venere, L. and Dominguez, A. and Favuzzi, C. and Fegan, S. J. and Franckowiak, Anna and Fukazawa, Yasushi and Funk, Stefan and Fusco, Piergiorgio and Gargano, Fabio and Gasparrini, Dario and Giglietto, Nicola and Giordano, F. and Giroletti, Marcello and Green, D. and Grenier, I. A. and Guillemot, L. and Guiriec, Sylvain and Hays, Elizabeth and Hewitt, John W. and Horan, D. and Johannesson, G. and Kensei, S. and Kuss, M. and Larsson, Stefan and Latronico, L. and Lemoine-Goumard, Marianne and Li, J. and Longo, Francesco and Loparco, Francesco and Lovellette, M. N. and Lubrano, Pasquale and Magill, Jeffrey D. and Maldera, Simone and Mazziotta, Mario Nicola and McEnery, J. E. and Michelson, P. F. and Mitthumsiri, W. and Mizuno, Tsunefumi and Monzani, Maria Elena and Morselli, Aldo and Moskalenko, Igor V. and Negro, M. and Nuss, E. and Ojha, R. and Omodei, Nicola and Orienti, M. and Orlando, E. and Palatiello, M. and Paliya, Vaidehi S. and Paneque, D. and Perkins, Jeremy S. and Persic, M. and Pesce-Rollins, Melissa and Petrosian, Vahe' and Piron, F. and Porter, Troy A. and Principe, G. and Raino, S. and Rando, Riccardo and Rani, B. and Razzano, Massimilano and Razzaque, Soebur and Reimer, A. and Reimer, Olaf and Reposeur, T. and Sgro, C. and Siskind, E. J. and Spandre, Gloria and Spinelli, P. and Suson, D. J. and Tajima, Hiroyasu and Thayer, J. B. and Thompson, David J. and Torres, Diego F. and Tosti, Gino and Troja, Eleonora and Valverde, J. and Vianello, Giacomo and Vogel, M. and Wood, K. and Yassine, M. and Alfaro, R. and Alvarez, C. and Alvarez, J. D. and Arceo, R. and Arteaga-Velazquez, J. C. and Rojas, D. Avila and Ayala Solares, H. A. and Becerril, A. and Belmont-Moreno, E. and BenZvi, S. Y. and Bernal, A. and Braun, J. and Brisbois, C. and Caballero-Mora, K. S. and Capistran, T. and Carraminana, A. and Casanova, Sabrina and Castillo, M. and Cotti, U. and Cotzomi, J. and Coutino de Leon, S. and De Leon, C. and De la Fuente, E. and Dichiara, S. and Dingus, B. L. and DuVernois, M. A. and Diaz-Velez, J. C. and Engel, K. and Enriquez-Rivera, O. and Fiorino, D. W. and Fleischhack, H. and Fraija, N. and Garcia-Gonzalez, J. A. and Garfias, F. and Gonzalez Munoz, A. and Gonzalez, M. M. and Goodman, J. A. and Hampel-Arias, Z. and Harding, J. P. and Hernandez, S. and Hernandez-Almada, A. and Hona, B. and Hueyotl-Zahuantitla, F. and Hui, C. M. and Huntemeyer, P. and Iriarte, A. and Jardin-Blicq, A. and Joshi, V. and Kaufmann, S. and Lara, A. and Lauer, R. J. and Lee, W. H. and Lennarz, D. and Leon Vargas, H. and Linnemann, J. T. and Longinotti, A. L. and Luis-Raya, G. and Luna-Garcia, R. and Lopez-Coto, R. and Malone, K. and Marinelli, S. S. and Martinez, O. and Martinez-Castellanos, I. and Martinez-Castro, J. and Martinez-Huerta, H. and Matthews, J. A. and Miranda-Romagnoli, P. and Moreno, E. and Mostafa, M. and Nayerhoda, A. and Nellen, L. and Newbold, M. and Nisa, M. U. and Noriega-Papaqui, R. and Pelayo, R. and Pretz, J. and Perez-Perez, E. G. and Ren, Z. and Rho, C. D. and Riviere, C. and Rosa-Gonzalez, D. and Rosenberg, M. and Ruiz-Velasco, E. and Salazar, H. and Greus, F. Salesa and Sandoval, A. and Schneider, M. and Arroyo, M. Seglar and Sinnis, G. and Smith, A. J. and Springer, R. W. and Surajbali, P. and Taboada, Ignacio and Tibolla, O. and Tollefson, K. and Torres, I. and Ukwatta, Tilan N. and Villasenor, L. and Weisgarber, T. and Westerhoff, Stefan and Wisher, I. G. and Wood, J. and Yapici, Tolga and Yodh, G. and Zepeda, A. and Zhou, H.}, title = {VERITAS and Fermi-LAT Observations of TeV Gamma-Ray Sources Discovered by HAWC in the 2HWC Catalog}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {866}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, organization = {VERITAS Collaboration Fermi-LAT Collaboration HAWC Collaboration}, issn = {0004-637X}, doi = {10.3847/1538-4357/aade4e}, pages = {18}, year = {2018}, abstract = {The High Altitude Water Cherenkov (HAWC) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100 GeV) gamma-ray sources based on 507 days of observation. Among these, 19 sources are not associated with previously known teraelectronvolt (TeV) gamma-ray sources. We have studied 14 of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1 TeV-30 TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected 14 new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected gigaelectronvolt (GeV) gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC, and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region.}, language = {en} } @article{AliuArchambaultArlenetal.2014, author = {Aliu, E. and Archambault, S. and Arlen, T. and Aune, T. and Barnacka, Anna and Beilicke, M. and Benbow, W. and Berger, K. and Bird, R. and Bouvier, A. and Buckley, J. H. and Bugaev, V. and Cerruti, M. and Chen, X. and Ciupik, L. and Collins-Hughes, E. and Connolly, M. P. and Cui, W. and Dumm, J. and Eisch, J. D. and Falcone, A. and Federici, S. and Feng, Q. and Finley, J. P. and Fleischhack, H. and Fortin, P. and Fortson, L. and Furniss, A. and Galante, N. and Gillanders, G. H. and Griffin, S. and Griffiths, S. T. and Grube, J. and Gyuk, G. and Hakansson, N. and Hanna, D. and Holder, J. and Hughes, G. and Hughes, Z. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kar, P. and Kertzman, M. and Khassen, Y. and Kieda, D. and Krawczynski, H. and Krennrich, F. and Lang, M. J. and Madhavan, A. S. and Majumdar, P. and McArthur, S. and McCann, A. and Meagher, K. and Millis, J. and Moriarty, P. and Mukherjee, R. and Nelson, T. and Nieto, D. and Ong, R. A. and Otte, A. N. and Park, N. and Perkins, J. S. and Pohl, M. and Popkow, A. and Prokoph, H. and Quinn, J. and Ragan, K. and Rajotte, J. and Reyes, L. C. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Sadun, A. and Santander, M. and Sembroski, G. H. and Shahinyan, K. and Sheidaei, F. and Smith, A. W. and Staszak, D. and Telezhinsky, Igor O. and Theiling, M. and Tyler, J. and Varlotta, A. and Vassiliev, V. V. and Vincent, S. and Wakely, S. P. and Weekes, T. C. and Weinstein, A. and Welsing, R. and Wilhelm, Alina and Williams, D. A. and Zitzer, B. and Boettcher, Markus and Fumagalli, M.}, title = {Investigating broadband variability of the TeV blazar 1ES 1959+650}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {797}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {2}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, organization = {Veritas Collaboration}, issn = {0004-637X}, doi = {10.1088/0004-637X/797/2/89}, pages = {11}, year = {2014}, abstract = {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 the 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.}, language = {en} } @article{AbeysekaraArcherAuneetal.2018, author = {Abeysekara, A. U. and Archer, A. and Aune, Taylor and Benbow, Wystan and Bird, Ralph and Brose, Robert and Buchovecky, M. and Bugaev, V. and Cui, Wei and Daniel, M. K. and Falcone, A. and Feng, Qi and Finley, John P. and Fleischhack, H. and Flinders, A. and Fortson, L. and Furniss, Amy and Gotthelf, Eric V. and Grube, J. and Hanna, David and Hervet, O. and Holder, J. and Huang, K. and Hughes, G. and Humensky, T. B. and Huetten, M. and Johnson, Caitlin A. and Kaaret, Philip and Kar, P. and Kelley-Hoskins, N. and Kertzman, M. and Kieda, David and Krause, Maria and Kumar, S. and Lang, M. J. and Lin, T. T. Y. and Maier, Gernot and McArthur, S. and Moriarty, P. and Mukherjee, Reshmi and Ong, R. A. and Otte, Adam Nepomuk and Pandel, Dirk and Park, Nahee and Petrashyk, A. and Pohl, Martin and Popkow, Alexis and Pueschel, Elisa and Quinn, J. and Ragan, K. and Reynolds, P. T. and Richards, Gregory T. and Roache, E. and Rousselle, J. and Rulten, C. and Sadeh, I. and Santander, M. and Sembroski, G. H. and Shahinyan, Karlen and Tyler, J. and Vassiliev, V. V. and Wakely, S. P. and Ward, J. E. and Weinstein, A. and Wells, R. M. and Wilcox, P. and Wilhelm, Alina and Williams, David A. and Zitzer, B.}, title = {A Very High Energy gamma-Ray Survey toward the Cygnus Region of the Galaxy}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {861}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {2}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.3847/1538-4357/aac4a2}, pages = {33}, year = {2018}, abstract = {We present results from deep observations toward the Cygnus region using 300 hr of very high energy (VHE)gamma-ray data taken with the VERITAS Cerenkov telescope array and over 7 yr of high-energy.-ray data taken with the Fermi satellite at an energy above 1 GeV. As the brightest region of diffuse gamma-ray emission in the northern sky, the Cygnus region provides a promising area to probe the origins of cosmic rays. We report the identification of a potential Fermi-LAT counterpart to VER J2031+415 (TeV J2032+4130) and resolve the extended VHE source VER J2019+368 into two source candidates (VER J2018+367* and VER J2020+368*) and characterize their energy spectra. The Fermi-LAT morphology of 3FGL J2021.0+4031e (the Gamma Cygni supernova remnant) was examined, and a region of enhanced emission coincident with VER J2019+407 was identified and jointly fit with the VERITAS data. By modeling 3FGL J2015.6+3709 as two sources, one located at the location of the pulsar wind nebula CTB 87 and one at the quasar QSO J2015+371, a continuous spectrum from 1 GeV to 10 TeV was extracted for VER J2016+371 (CTB 87). An additional 71 locations coincident with Fermi-LAT sources and other potential objects of interest were tested for VHE gamma-ray emission, with no emission detected and upper limits on the differential flux placed at an average of 2.3\% of the Crab Nebula flux. We interpret these observations in a multiwavelength context and present the most detailed gamma-ray view of the region to date.}, language = {en} } @article{AliuAuneBeheraetal.2014, author = {Aliu, E. and Aune, T. and Behera, B. and Beilicke, M. and Benbow, W. and Berger, K. and Bird, R. and Bouvier, A. and Buckley, J. H. and Bugaev, V. and Cerruti, M. and Chen, Xuhui and Ciupik, L. and Connolly, M. P. and Cui, W. and Dumm, J. and Dwarkadas, Vikram V. and Errando, M. and Falcone, A. and Federici, Simone and Feng, Q. and Finley, J. P. and Fleischhack, H. and Fortin, P. and Fortson, L. and Furniss, A. and Galante, N. and Gillanders, G. H. and Gotthelf, E. V. and Griffin, S. and Griffiths, S. T. and Grube, J. and Gyuk, G. and Hanna, D. and Holder, J. and Hughes, G. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kargaltsev, O. and Kertzman, M. and Khassen, Y. and Kieda, D. and Krennrich, F. and Lang, M. J. and Madhavan, A. S. and Maier, G. and McArthur, S. and McCann, A. and Millis, J. and Moriarty, P. and Mukherjee, R. and Nieto, D. and Ong, R. A. and Otte, A. N. and Pandel, D. and Park, N. and Pohl, Martin and Popkow, A. and Prokoph, H. and Quinn, J. and Ragan, K. and Rajotte, J. and Reyes, L. C. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Roberts, M. and Sembroski, G. H. and Shahinyan, K. and Smith, A. W. and Staszak, D. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Vincent, S. and Wakely, S. P. and Weinstein, A. and Welsing, R. and Wilhelm, Alina and Williams, D. A. and Zitzer, B.}, title = {Spatially resolving the very high energy emission from MRGO J2019+37 wih veritas}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {788}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/788/1/78}, pages = {10}, year = {2014}, abstract = {We present very high energy (VHE) imaging of MGRO J2019+37 obtained with the VERITAS observatory. The bright extended (similar to 2 degrees) unidentified Milagro source is located toward the rich star formation region Cygnus-X. MGRO J2019+37 is resolved into two VERITAS sources. The faint, point-like source VER J2016+371 overlaps CTB 87, a filled-center remnant (SNR) with no evidence of a supernova remnant shell at the present time. Its spectrum is well fit in the 0.65-10 TeV energy range by a power-law model with photon index 2.3 +/- 0.4. VER J2019+378 is a bright extended (similar to 1 degrees) source that likely accounts for the bulk of the Milagro emission and is notably coincident with PSR J2021+3651 and the star formation region Sh 2-104. Its spectrum in the range 1-30 TeV is well fit with a power-law model of photon index 1.75 +/- 0.3, among the hardest values measured in the VHE band, comparable to that observed near Vela-X. We explore the unusual spectrum and morphology in the radio and X-ray bands to constrain possible emission mechanisms for this source.}, language = {en} } @article{ArchambaultArcherBarnackaetal.2016, author = {Archambault, S. and Archer, A. and Barnacka, Anna and Behera, B. and Beilicke, M. and Benbow, W. and Berger, K. and Bird, R. and B{\"o}ttcher, Markus and Buckley, J. H. and Bugaev, V. and Cardenzana, J. V. and Cerruti, M. and Chen, Xuhui and Christiansen, J. L. and Ciupik, L. and Collins-Hughes, E. and Connolly, M. P. and Cui, W. and Dickinson, H. J. and Dumm, J. and Eisch, J. D. and Errando, M. and Falcone, A. and Federici, Simone and Feng, Q. and Finley, J. P. and Fleischhack, H. and Fortson, L. and Furniss, A. and Gillanders, G. H. and Godambe, S. and Griffin, S. and Griffiths, S. T. and Grube, J. and Gyuk, G. and Hakansson, Nils and Hanna, D. and Holder, J. and Hughes, G. and Johnson, C. A. and Kaaret, P. and Kar, P. and Kertzman, M. and Khassen, Y. and Kieda, D. and Krawczynski, H. and Kumar, S. and Lang, M. J. and Madhavan, A. S. and Maier, G. and McArthur, S. and McCann, A. and Meagher, K. and Millis, J. and Moriarty, P. and Nelson, T. and Nieto, D. and Ong, R. A. and Otte, A. N. and Park, N. and Perkins, J. S. and Pohl, Martin and Popkow, A. and Prokoph, H. and Pueschel, Elisa and Quinn, J. and Ragan, K. and Rajotte, J. and Reyes, L. C. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Sembroski, G. H. and Shahinyan, K. and Smith, A. W. and Staszak, D. and Sweeney, K. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Varlotta, A. and Vassiliev, V. V. and Wakely, S. P. and Welsing, R. and Wilhelm, Alina and Williams, D. A. and Zitzer, B.}, title = {Discovery of very high energy gamma rays from 1ES 1440+122}, series = {Monthly notices of the Royal Astronomical Society}, volume = {461}, journal = {Monthly notices of the Royal Astronomical Society}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stw1319}, pages = {202 -- 208}, year = {2016}, language = {en} } @article{AliuArchambaultArlenetal.2014, author = {Aliu, E. and Archambault, S. and Arlen, T. and Aune, T. and Behera, B. and Beilicke, M. and Benbow, W. and Berger, K. and Bird, R. and Bouvier, A. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cerruti, M. and Chen, Xuhui and Ciupik, L. and Connolly, M. P. and Cui, W. and Duke, C. and Dumm, J. and Errando, M. and Falcone, A. and Federici, S. and Feng, Q. and Finley, J. P. and Fleischhack, H. and Fortin, P. and Fortson, L. and Furniss, A. and Galante, N. and Gillanders, G. H. and Griffin, S. and Griffiths, S. T. and Grube, J. and Gyuk, G. and Hanna, D. and Holder, J. and Hughes, G. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kertzman, M. and Khassen, Y. and Kieda, D. and Krawczynski, H. and Krennrich, F. and Lang, M. J. and Madhavan, A. S. and Maier, G. and Majumdar, P. and McArthur, S. and McCann, A. and Meagher, K. and Millis, J. and Moriarty, P. and Mukherjee, R. and Nieto, D. and Ong, R. A. and Otte, A. N. and Park, N. and Perkins, J. S. and Pohl, M. and Popkow, A. and Prokoph, H. and Quinn, J. and Ragan, K. and Reyes, L. C. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Sembroski, G. H. and Smith, A. W. and Staszak, D. and Telezhinsky, Igor O. and Theiling, M. and Varlotta, A. and Vassiliev, V. V. and Vincent, S. and Wakely, S. P. and Weekes, T. C. and Weinstein, A. and Welsing, R. and Williams, D. A. and Zajczyk, A. and Zitzer, B.}, title = {A three-year multi-wavelenght study of the very-high-energy gamma-ray Blazar 1ES 0229+200}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {782}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/782/1/13}, pages = {12}, year = {2014}, language = {en} } @article{ArcherBenbowBirdetal.2016, author = {Archer, A. and Benbow, W. and Bird, R. and Buchovecky, M. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cardenzana, J. V. and Cerruti, M. and Chen, Xuhui and Ciupik, L. and Collins-Hughes, E. and Connolly, M. P. and Eisch, J. D. and Falcone, A. and Feng, Q. and Finley, J. P. and Fleischhack, H. and Flinders, A. and Fortson, L. and Furniss, A. and Gillanders, G. H. and Griffin, S. and Grube, J. and Gyuk, G. and Hakansson, Nils and Hanna, D. and Holder, J. and Humensky, T. B. and Huetten, M. and Johnson, C. A. and Kaaret, P. and Kar, P. and Kelley-Hoskins, N. and Kertzman, M. and Kieda, D. and Krause, M. and Krennrich, F. and Kumar, S. and Lang, M. J. and McArthur, S. and McCann, A. and Meagher, K. and Millis, J. and Moriarty, P. and Mukherjee, R. and Nieto, D. and Ong, R. A. and Park, N. and Pelassa, V. and Pohl, Martin and Popkow, A. and Pueschel, Elisa and Quinn, J. and Ragan, K. and Ratliff, G. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Rousselle, J. and Santander, M. and Sembroski, G. H. and Shahinyan, K. and Smith, A. W. and Staszak, D. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Vassiliev, V. V. and Wakely, S. P. and Weiner, O. M. and Weinstein, A. and Wilhelm, Alina and Williams, D. A. and Zitzer, B. and Yusef-Zadeh, F.}, title = {TEV GAMMA-RAY OBSERVATIONS OF THE GALACTIC CENTER RIDGE BY VERITAS}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {821}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.3847/0004-637X/821/2/129}, pages = {162 -- 167}, year = {2016}, abstract = {The Galactic Center ridge has been observed extensively in the past by both GeV and TeV gamma-ray instruments revealing a wealth of structure, including a diffuse component and the point sources G0.9+0.1 (a composite supernova remnant) and Sgr A* (believed to be associated with the supermassive black hole located at the center of our Galaxy). Previous very high energy (VHE) gamma-ray observations with the H.E.S.S.. experiment have also detected an extended TeV gamma-ray component along the Galactic plane in the >300 GeV gamma-ray regime. Here we report on observations of the Galactic Center ridge from 2010 to 2014 by the VERITAS telescope array in the >2 TeV energy range. From these observations we (1) provide improved measurements of the differential energy spectrum for Sgr A* in the >2 TeV gamma-ray regime, (2) provide a detection in the >2 TeV gamma-ray emission from the composite SNR G0.9+0.1 and an improved determination of its multi-TeV gamma-ray energy spectrum, and. (3) report on the detection of VER J1746-289, a localized enhancement of >2 TeV gamma-ray emission along the Galactic plane.}, language = {en} } @article{AliuArchambaultArcheretal.2016, author = {Aliu, E. and Archambault, S. and Archer, A. and Benbow, W. and Bird, R. and Biteau, Jonathan and Buchovecky, M. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cardenzana, J. V. and Cerruti, M. and Chen, Xuhui and Ciupik, L. and Connolly, M. P. and Cui, W. and Dickinson, H. J. and Eisch, J. D. and Falcone, A. and Feng, Q. and Finley, J. P. and Fleischhack, H. and Flinders, A. and Fortin, P. and Fortson, L. and Furniss, A. and Gillanders, G. H. and Griffin, S. and Grube, J. and Gyuk, G. and Huetten, M. and Hakansson, Nils and Holder, J. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kar, P. and Kelley-Hoskins, N. and Kertzman, M. and Kieda, D. and Krause, M. and Lang, M. J. and Loo, A. and Maier, G. and McArthur, S. and McCann, A. and Meagher, K. and Moriarty, P. and Mukherjee, R. and Nguyen, T. and Nieto, D. and Ong, R. A. and Otte, A. N. and Pandel, D. and Park, N. and Pelassa, V. and Petrashyk, A. and Pohl, M. and Popkow, A. and Pueschel, Elisa and Quinn, J. and Ragan, K. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Rulten, C. and Santander, M. and Sembroski, G. H. and Shahinyan, K. and Smith, A. W. and Staszak, D. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Varlotta, A. and Vincent, S. and Wakely, S. P. and Weiner, O. M. and Weinstein, A. and Wilhelm, Alina and Williams, D. A. and Zitzer, B. and Chernyakova, M. and Roberts, M. S. E.}, title = {A SEARCH FOR VERY HIGH ENERGY GAMMA RAYS FROM THE MISSING LINK BINARY PULSAR J1023+0038 WITH VERITAS}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {831}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.3847/0004-637X/831/2/193}, pages = {7}, year = {2016}, abstract = {The binary millisecond radio pulsar PSR J1023+0038 exhibits many characteristics similar to the gamma-ray binary system PSR B1259-63/LS 2883, making it an ideal candidate for the study of high-energy nonthermal emission. It has been the subject of multiwavelength campaigns following the disappearance of the pulsed radio emission in 2013 June, which revealed the appearance of an accretion disk around the neutron star. We present the results of very high energy (VHE) gamma-ray observations carried out by the Very Energetic Radiation Imaging Telescope Array System before and after this change of state. Searches for steady and pulsed emission of both data sets yield no significant gamma-ray signal above 100 GeV, and upper limits are given for both a steady and pulsed gamma-ray flux. These upper limits are used to constrain the magnetic field strength in the shock region of the PSR J1023+0038 system. Assuming that VHE gamma rays are produced via an inverse Compton mechanism in the shock region, we constrain the shock magnetic field to be greater than similar to 2 G before the disappearance of the radio pulsar and greater than similar to 10 G afterward.}, language = {en} } @article{ArchambaultArcherAuneetal.2016, author = {Archambault, S. and Archer, A. and Aune, T. and Barnacka, Anna and Benbow, W. and Bird, R. and Buchovecky, M. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cardenzana, J. V. and Cerruti, M. and Chen, Xuhui and Ciupik, L. and Collins-Hughes, E. and Connolly, M. P. and Cui, W. and Dickinson, H. J. and Dumm, J. and Eisch, J. D. and Falcone, A. and Feng, Q. and Finley, J. P. and Fleischhack, H. and Flinders, A. and Fortin, P. and Fortson, L. and Furniss, A. and Gillanders, G. H. and Griffin, S. and Grube, J. and Gyuk, G. and Huetten, M. and Hakansson, Nils and Hanna, D. and Holder, J. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kar, P. and Kelley-Hoskins, N. and Kertzman, M. and Khassen, Y. and Kieda, D. and Krause, M. and Krennrich, F. and Kumar, S. and Lang, M. J. and Maier, G. and McArthur, S. and McCann, A. and Meagher, K. and Millis, J. and Moriarty, P. and Mukherjee, R. and Nieto, D. and Ong, R. A. and Otte, A. N. and Pandel, D. and Park, N. and Pelassa, V. and Pohl, Martin and Popkow, A. and Pueschel, Elisa and Quinn, J. and Ragan, K. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Rousselle, J. and Rulten, C. and Santander, M. and Sembroski, G. H. and Shahinyan, K. and Smith, A. W. and Staszak, D. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Vincent, S. and Wakely, S. P. and Weiner, O. M. and Weinstein, A. and Wilhelm, Alina and Williams, D. A. and Zitzer, B.}, title = {EXCEPTIONALLY BRIGHT TEV FLARES FROM THE BINARY LS I+61 degrees 303}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters}, volume = {817}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {2041-8205}, doi = {10.3847/2041-8205/817/1/L7}, pages = {6}, year = {2016}, abstract = {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.}, language = {en} }