TY - JOUR A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, W. A1 - Bird, R. A1 - Bourbeau, E. A1 - Brantseg, T. A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cerruti, M. A1 - Christiansen, J. L. A1 - Connolly, M. P. A1 - Cui, W. A1 - Daniel, M. K. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Geringer-Sameth, A. A1 - Griffin, S. A1 - Grube, J. A1 - Hütten, M. A1 - Hakansson, N. A1 - Hanna, D. A1 - Hervet, O. A1 - Holder, J. A1 - Hughes, G. A1 - Hummensky, B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, D. A1 - Koushiappas, S. A1 - Krause, M. A1 - Krennrich, F. A1 - Lang, M. J. A1 - Lin, T. T. Y. A1 - McArthur, S. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Pohl, M. A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rulten, C. A1 - Sadeh, I. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Trepanier, S. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Wilcox, P. A1 - Williams, D. A. A1 - Zitzer, B. T1 - Dark matter constraints from a joint analysis of dwarf Spheroidal galaxy observations with VERITAS JF - Physical review : D, Particles, fields, gravitation, and cosmology N2 - We present constraints on the annihilation cross section of weakly interacting massive particles dark matter based on the joint statistical analysis of four dwarf galaxies with VERITAS. These results are derived from an optimized photon weighting statistical technique that improves on standard imaging atmospheric Cherenkov telescope (IACT) analyses by utilizing the spectral and spatial properties of individual photon events. We report on the results of similar to 230 hours of observations of five dwarf galaxies and the joint statistical analysis of four of the dwarf galaxies. We find no evidence of gamma-ray emission from any individual dwarf nor in the joint analysis. The derived upper limit on the dark matter annihilation cross section from the joint analysis is 1.35 x 10(-23) cm(3) s(-1) at 1 TeV for the bottom quark (b (b) over bar) final state, 2.85 x 10(-24) cm(3) s(-1) at 1 TeV for the tau lepton (tau+tau(-)) final state and 1.32 x 10-25 cm(3) s(-1) at 1 TeV for the gauge boson (gamma gamma) final state. Y1 - 2017 U6 - https://doi.org/10.1103/PhysRevD.95.082001 SN - 2470-0010 SN - 2470-0029 VL - 95 IS - 8 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, W. A1 - Buchovecky, M. A1 - Bugaev, V. A1 - Cerruti, M. A1 - Connolly, M. P. A1 - Cui, W. A1 - Falcone, A. A1 - Alonso, M. Fernandez A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Griffin, S. A1 - Hutten, M. A1 - Hervet, O. A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Lang, M. J. A1 - Lin, T. T. Y. A1 - Maier, G. A1 - McArthur, S. A1 - Moriarty, P. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Pohl, M. A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rovero, A. C. A1 - Sadeh, I. A1 - Shahinyan, K. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tyler, J. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Weisgarber, T. A1 - Wilcox, P. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. T1 - Search for Magnetically Broadened Cascade Emission from Blazars with VERITAS JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - We present a search for magnetically broadened gamma-ray emission around active galactic nuclei (AGNs), using VERITAS observations of seven hard-spectrum blazars. A cascade process occurs when multi-TeV gamma-rays from an AGN interact with extragalactic background light (EBL) photons to produce electron-positron pairs, which then interact with cosmic microwave background photons via inverse-Compton scattering to produce gamma-rays. Due to the deflection of the electron- positron pairs, a non-zero intergalactic magnetic field (IGMF) would potentially produce detectable effects on the angular distribution of the cascade emission. In particular, an angular broadening compared to the unscattered emission could occur. Through non-detection of angularly broadened emission from 1ES 1218 vertical bar 304, the source with the largest predicted cascade fraction, we exclude a range of IGMF strengths around 10(-14) G at the 95% confidence level. The extent of the exclusion range varies with the assumptions made about the intrinsic spectrum of 1ES. 1218+304 and the EBL model used in the simulation of the cascade process. All of the sources are used to set limits on the flux due to extended emission. KW - BL Lacertae objects: general KW - galaxies: active KW - gamma rays: galaxies KW - magnetic fields Y1 - 2017 U6 - https://doi.org/10.3847/1538-4357/835/2/288 SN - 0004-637X SN - 1538-4357 VL - 835 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Archer, A. A1 - Barnacka, Anna A1 - Beilicke, M. A1 - Benbow, W. A1 - Berger, K. A1 - Bird, R. A1 - Biteau, Jonathan A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, W. A1 - Chen, Xiaoming A1 - Ciupik, L. A1 - Connolly, M. P. A1 - Cui, W. A1 - Dickinson, H. J. A1 - Dumm, J. A1 - Eisch, J. D. A1 - Falcone, A. A1 - Federici, Simone A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Galante, N. A1 - Griffin, S. A1 - Griffiths, S. T. A1 - Grube, J. A1 - Gyuk, G. A1 - Hakansson, Nils A1 - Hanna, D. A1 - Holder, J. A1 - Hughes, G. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kertzman, M. A1 - Khassen, Y. A1 - Kieda, D. A1 - Krawczynski, H. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Perkins, J. S. A1 - Pohl, Manuela A1 - Popkow, A. A1 - Prokoph, H. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Rajotte, J. A1 - Reyes, L. C. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Varlotta, A. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Welsing, R. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zajczyk, A. A1 - Zitzer, B. T1 - Very-high energy observations of the galactic center region by veritas IN 2010-2012 JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - The Galactic center is an interesting region for high-energy (0.1-100 GeV) and very-high-energy (E > 100 GeV) gamma-ray observations. Potential sources of GeV/TeV gamma-ray emission have been suggested, e.g., the accretion of matter onto the supermassive black hole, cosmic rays from a nearby supernova remnant (e.g., Sgr A East), particle acceleration in a plerion, or the annihilation of dark matter particles. The Galactic center has been detected by EGRET and by Fermi/LAT in the MeV/GeV energy band. At TeV energies, the Galactic center was detected with moderate significance by the CANGAROO and Whipple 10 m telescopes and with high significance by H.E.S.S., MAGIC, and VERITAS. We present the results from three years of VERITAS observations conducted at large zenith angles resulting in a detection of the Galactic center on the level of 18 standard deviations at energies above similar to 2.5 TeV. The energy spectrum is derived and is found to be compatible with hadronic, leptonic, and hybrid emission models discussed in the literature. Future, more detailed measurements of the high-energy cutoff and better constraints on the high-energy flux variability will help to refine and/or disentangle the individual models. KW - astroparticle physics KW - black hole physics KW - Galaxy: center KW - gamma rays: galaxies KW - methods: data analysis KW - radiation mechanisms: non-thermal Y1 - 2014 U6 - https://doi.org/10.1088/0004-637X/790/2/149 SN - 0004-637X SN - 1538-4357 VL - 790 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Aliu, E. A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, W. A1 - Bird, R. A1 - Biteau, Jonathan A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Connolly, M. P. A1 - Cui, W. A1 - Dickinson, H. J. A1 - Eisch, J. D. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Flinders, A. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Grube, J. A1 - Gyuk, G. A1 - Huetten, M. A1 - Hakansson, Nils A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Lang, M. J. A1 - Loo, A. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nguyen, T. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Pandel, D. A1 - Park, N. A1 - Pelassa, V. A1 - Petrashyk, A. A1 - Pohl, M. A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rulten, C. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Varlotta, A. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. A1 - Chernyakova, M. A1 - Roberts, M. S. E. T1 - A SEARCH FOR VERY HIGH ENERGY GAMMA RAYS FROM THE MISSING LINK BINARY PULSAR J1023+0038 WITH VERITAS JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - 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. KW - binaries: general KW - gamma rays: general KW - pulsars: general KW - pulsars: individual (PSR J1023+0038) Y1 - 2016 U6 - https://doi.org/10.3847/0004-637X/831/2/193 SN - 0004-637X SN - 1538-4357 VL - 831 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Orienti, M. A1 - Finke, J. A1 - Raiteri, C. M. A1 - Hovatta, T. A1 - Larsson, J. A1 - Max-Moerbeck, W. A1 - Perkins, J. A1 - Readhead, A. C. S. A1 - Richards, J. L. A1 - Beilicke, M. A1 - Benbow, W. A1 - Berger, K. A1 - Bird, R. A1 - Bugaev, V. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Dickinson, H. J. A1 - Eisch, J. D. A1 - Errando, M. A1 - Falcone, A. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Gerard, L. A1 - Gillanders, G. H. A1 - Griffiths, S. T. A1 - Grube, J. A1 - Gyuk, G. A1 - Hakansson, Nils A1 - Holder, J. A1 - Humensky, T. B. A1 - Kar, P. A1 - Kertzman, M. A1 - Khassen, Y. A1 - Kieda, D. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McCann, A. A1 - Meagher, K. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Pohl, Manuela A1 - Popkow, A. A1 - Prokoph, H. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rousselle, J. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Varlotta, A. A1 - Vassiliev, V. V. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Welsing, R. A1 - Williams, D. A. A1 - Zitzer, B. T1 - The most powerful flaring activity from the NLSyl PMN J0948+0022 JF - Monthly notices of the Royal Astronomical Society N2 - We report on multifrequency observations performed during 2012 December-2013 August of the first narrow-line Seyfert 1 galaxy detected in gamma-rays, PMN J0948+0022 (z = 0.5846). A y -ray flare was observed by the Large Area Telescope on board Fermi during 2012 December-2013 January, reaching a daily peak flux in the 0.1-100 GeV energy range of (155 31) x 10 8 ph cm(-2) S-1 on 2013 January 1, corresponding to an apparent isotropic luminosity of similar to 1.5 x 1048 erg s(-1). The y -ray flaring period triggered Swift and Very Energetic Radiation Imaging Telescope Array System (VERITAS) observations in addition to radio and optical monitoring by Owens Valley Radio Observatory, Monitoring Of Jets in Active galactic nuclei with VLBA Experiments, and Catalina Real-time Transient Survey. A strong flare was observed in optical, UV, and X-rays on 2012 December 30, quasi-simultaneously to the y -ray flare, reaching a record flux for this source from optical to y gamma-rays. VERITAS observations at very high energy (E > 100 GeV) during 2013 January 6-17 resulted in an upper limit of F>0.2 Trev < 4.0 x 10(-12) ph cm(-2) s(-1). We compared the spectral energy distribution (SED) of the flaring state in 2013 January with that of an intermediate state observed in 2011. The two SEDs, modelled as synchrotron emission and an external Compton scattering of seed photons from a dust torus, can be modelled by changing both the electron distribution parameters and the magnetic field. KW - galaxies: active-galaxies: individual: PMN J0948+0022 KW - galaxies: nuclei KW - galaxies: Seyfert KW - gamma-rays: general Y1 - 2015 U6 - https://doi.org/10.1093/mnras/stu2251 SN - 0035-8711 SN - 1365-2966 VL - 446 IS - 3 SP - 2456 EP - 2467 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Aliu, E. A1 - Archambault, S. A1 - Archer, A. A1 - Aune, T. A1 - Barnacka, Anna A1 - Beilicke, M. A1 - Benbow, W. A1 - Bird, R. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Connolly, M. P. A1 - Cui, W. A1 - Dickinson, H. J. A1 - Dumm, J. A1 - Eisch, J. D. A1 - Errando, M. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Griffiths, S. T. A1 - Grube, J. A1 - Gyuk, G. A1 - Kansson, N. H. A. A1 - Hanna, D. A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Lyutikov, M. A1 - Madhavan, A. S. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Millis, J. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Pohl, Manuela A1 - Popkow, A. A1 - Prokoph, H. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reyes, L. C. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Varlotta, A. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Williams, D. A. A1 - Zajczyk, A. A1 - Zitzer, B. T1 - A search for pulsations from geminga above 100 GeV with veritas JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - 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. KW - gamma rays: stars KW - pulsars: general KW - pulsars: individual (PSR J0633+1746, Geminga) Y1 - 2015 U6 - https://doi.org/10.1088/0004-637X/800/1/61 SN - 0004-637X SN - 1538-4357 VL - 800 IS - 1 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, W. A1 - Bird, R. A1 - Biteau, Jonathan A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Connolly, M. P. A1 - Cui, W. A1 - Eisch, J. D. A1 - Errando, M. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Grube, J. A1 - Gyuk, G. A1 - Huetten, M. A1 - Hakansson, Nils A1 - Hanna, D. A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nguyen, T. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Perkins, J. S. A1 - Pichel, A. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rovero, A. C. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Williams, D. A. A1 - Zitzer, B. A1 - Fumagalli, M. A1 - Prochaska, J. X. T1 - UPPER LIMITS FROM FIVE YEARS OF BLAZAR OBSERVATIONS WITH THE VERITAS CHERENKOV TELESCOPES JF - The astronomical journal N2 - Between the beginning of its full-scale scientific operations in 2007 and 2012, the VERITAS Cherenkov telescope array observed more than 130 blazars; of these, 26 were detected as very-high-energy (VHE; E > 100 GeV) gamma-ray sources. In this work, we present the analysis results of a sample of 114 undetected objects. The observations constitute a total live-time of similar to 570 hr. The sample includes several unidentified Fermi-Large Area Telescope (LAT) sources (located at high Galactic latitude) as well as all the sources from the second Fermi-LAT catalog that are contained within the field of view of the VERITAS observations. We have also performed optical spectroscopy measurements in order to estimate the redshift of some of these blazars that do not have spectroscopic distance estimates. We present new optical spectra from the Kast instrument on the Shane telescope at the Lick observatory for 18 blazars included in this work, which allowed for the successful measurement or constraint on the redshift of four of them. For each of the blazars included in our sample, we provide the flux upper limit in the VERITAS energy band. We also study the properties of the significance distributions and we present the result of a stacked analysis of the data set, which shows a 4s excess. KW - BL Lacertae objects: general KW - galaxies: active KW - gamma rays: galaxies KW - radiation mechanisms: non-thermal Y1 - 2016 U6 - https://doi.org/10.3847/0004-6256/151/6/142 SN - 0004-6256 SN - 1538-3881 VL - 151 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Archambault, S. A1 - Archer, A. A1 - Barnacka, Anna A1 - Behera, B. A1 - Beilicke, M. A1 - Benbow, W. A1 - Berger, K. A1 - Bird, R. A1 - Böttcher, Markus A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Christiansen, J. L. A1 - Ciupik, L. A1 - Collins-Hughes, E. A1 - Connolly, M. P. A1 - Cui, W. A1 - Dickinson, H. J. A1 - Dumm, J. A1 - Eisch, J. D. A1 - Errando, M. A1 - Falcone, A. A1 - Federici, Simone A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Godambe, S. A1 - Griffin, S. A1 - Griffiths, S. T. A1 - Grube, J. A1 - Gyuk, G. A1 - Hakansson, Nils A1 - Hanna, D. A1 - Holder, J. A1 - Hughes, G. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kertzman, M. A1 - Khassen, Y. A1 - Kieda, D. A1 - Krawczynski, H. A1 - Kumar, S. A1 - Lang, M. J. A1 - Madhavan, A. S. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Millis, J. A1 - Moriarty, P. A1 - Nelson, T. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Perkins, J. S. A1 - Pohl, Martin A1 - Popkow, A. A1 - Prokoph, H. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Rajotte, J. A1 - Reyes, L. C. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Sweeney, K. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Varlotta, A. A1 - Vassiliev, V. V. A1 - Wakely, S. P. A1 - Welsing, R. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. T1 - Discovery of very high energy gamma rays from 1ES 1440+122 JF - Monthly notices of the Royal Astronomical Society KW - BL Lacertae objects: general KW - gamma-rays: general Y1 - 2016 U6 - https://doi.org/10.1093/mnras/stw1319 SN - 0035-8711 SN - 1365-2966 VL - 461 SP - 202 EP - 208 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Archambault, S. A1 - Archer, A. A1 - Aune, T. A1 - Barnacka, Anna A1 - Benbow, W. A1 - Bird, R. A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Collins-Hughes, E. A1 - Connolly, M. P. A1 - Cui, W. A1 - Dickinson, H. J. A1 - Dumm, J. A1 - Eisch, J. D. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Flinders, A. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Grube, J. A1 - Gyuk, G. A1 - Huetten, M. A1 - Hakansson, Nils A1 - Hanna, D. A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Khassen, Y. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Millis, J. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Pandel, D. A1 - Park, N. A1 - Pelassa, V. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rousselle, J. A1 - Rulten, C. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. T1 - EXCEPTIONALLY BRIGHT TEV FLARES FROM THE BINARY LS I+61 degrees 303 JF - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters N2 - 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. KW - binaries: general KW - gamma-rays: general KW - stars: individual (LS I+61 degrees 303, VER J0240+612) KW - X-rays: binaries Y1 - 2016 U6 - https://doi.org/10.3847/2041-8205/817/1/L7 SN - 2041-8205 SN - 2041-8213 VL - 817 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Aliu, E. A1 - Aune, T. A1 - Behera, B. A1 - Beilicke, M. A1 - Benbow, W. A1 - Berger, K. A1 - Bird, R. A1 - Bouvier, A. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Connolly, M. P. A1 - Cui, W. A1 - Dumm, J. A1 - Dwarkadas, Vikram V. A1 - Errando, M. A1 - Falcone, A. A1 - Federici, Simone A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Galante, N. A1 - Gillanders, G. H. A1 - Gotthelf, E. V. A1 - Griffin, S. A1 - Griffiths, S. T. A1 - Grube, J. A1 - Gyuk, G. A1 - Hanna, D. A1 - Holder, J. A1 - Hughes, G. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kargaltsev, O. A1 - Kertzman, M. A1 - Khassen, Y. A1 - Kieda, D. A1 - Krennrich, F. A1 - Lang, M. J. A1 - Madhavan, A. S. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Millis, J. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Pandel, D. A1 - Park, N. A1 - Pohl, Martin A1 - Popkow, A. A1 - Prokoph, H. A1 - Quinn, J. A1 - Ragan, K. A1 - Rajotte, J. A1 - Reyes, L. C. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Roberts, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Welsing, R. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. T1 - Spatially resolving the very high energy emission from MRGO J2019+37 wih veritas JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - 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. KW - gamma rays : stars KW - pulsars : individual (PSR J2021+3651) KW - supernovae : individual (CTB 87) Y1 - 2014 U6 - https://doi.org/10.1088/0004-637X/788/1/78 SN - 0004-637X SN - 1538-4357 VL - 788 IS - 1 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, W. A1 - Bird, Ralph A1 - Bourbeau, E. A1 - Bouvier, A. A1 - Buchovecky, M. A1 - Bugaev, V. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Ciupik, L. A1 - Connolly, M. P. A1 - Cui, W. A1 - Daniel, M. K. A1 - Errando, M. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Hanna, D. A1 - Hervet, O. A1 - Holder, J. A1 - Hughes, G. A1 - Humensky, T. B. A1 - Hutten, M. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Lang, M. J. A1 - Lin, T. T. Y. A1 - Maier, G. A1 - McArthur, S. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rulten, C. A1 - Sadeh, I. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Trepanier, S. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Wilcox, P. A1 - Williams, D. A. A1 - Zitzer, B. T1 - Gamma-ray observations under bright moonlight with VERITAS JF - Astroparticle physics N2 - Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive photomultiplier tube (PMT) cameras. Exposure to high levels of background illumination degrades the efficiency of and potentially destroys these photo-detectors over time, so IACTs cannot be operated in the same configuration in the presence of bright moonlight as under dark skies. Since September 2012, observations have been carried out with the VERITAS IACTs under bright moonlight (defined as about three times the night-sky-background (NSB) of a dark extragalactic field, typically occurring when Moon illumination > 35%) in two observing modes, firstly by reducing the voltage applied to the PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to the cameras. This has allowed observations at up to about 30 times previous NSB levels (around 80% Moon illumination), resulting in 30% more observing time between the two modes over the course of a year. These additional observations have already allowed for the detection of a flare from the 1ES 1727 + 502 and for an observing program targeting a measurement of the cosmic-ray positron fraction. We provide details of these new observing modes and their performance relative to the standard VERITAS observations. (C) 2017 Elsevier B.V. All rights reserved. KW - Instrumentation KW - Moonlight KW - Observing methods KW - VERITAS KW - IACT Y1 - 2017 U6 - https://doi.org/10.1016/j.astropartphys.2017.03.001 SN - 0927-6505 SN - 1873-2852 VL - 91 SP - 34 EP - 43 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Aliu, E. A1 - Aune, T. A1 - Barnacka, Anna A1 - Beilicke, M. A1 - Benbow, W. A1 - Berger, K. A1 - Biteau, Jonathan A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Connaughton, V. A1 - Cui, W. A1 - Dickinson, H. J. A1 - Eisch, J. D. A1 - Errando, M. A1 - Falcone, A. A1 - Federici, Simone A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Galante, N. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Griffiths, S. T. A1 - Grube, J. A1 - Gyuk, G. A1 - Hakansson, Nils A1 - Hanna, D. A1 - Holder, J. A1 - Hughes, G. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kertzman, M. A1 - Khassen, Y. A1 - Kieda, D. A1 - Krawczynski, H. A1 - Krennrich, F. A1 - Lang, M. J. A1 - Madhavan, A. S. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Millis, J. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Pohl, Martin A1 - Popkow, A. A1 - Prokoph, H. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Rajotte, J. A1 - Reyes, L. C. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Varlotta, A. A1 - Vassiliev, V. V. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Welsing, R. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. A1 - McEnery, J. E. A1 - Perkins, J. S. A1 - Veres, P. A1 - Zhu, S. T1 - Constraints on very high energy emission from GRB 130427A JF - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters N2 - Prompt emission from the very fluent and nearby (z = 0.34) gamma-ray burst GRB130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope on the Fermi Gamma-Ray Space Telescope for similar to 70 ks after the initial burst. The persistent, hard-spectrum, high-energy emission suggests that the highest-energy gamma rays may have been produced via synchrotron self-Compton processes though there is also evidence that the high-energy emission may instead be an extension of the synchrotron spectrum. VERITAS, a ground-based imaging atmospheric Cherenkov telescope array, began follow-up observations of GRB130427A similar to 71 ks (similar to 20 hr) after the onset of the burst. The GRB was not detected with VERITAS; however, the high elevation of the observations, coupled with the low redshift of the GRB, make VERITAS a very sensitive probe of the emission from GRB130427A for E > 100 GeV. The non-detection and consequent upper limit derived place constraints on the synchrotron self-Compton model of high-energy gamma-ray emission from this burst. KW - gamma-ray burst: individual (GRB 130427A) Y1 - 2014 U6 - https://doi.org/10.1088/2041-8205/795/1/L3 SN - 2041-8205 SN - 2041-8213 VL - 795 IS - 1 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Abeysekara, A. U. A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, W. A1 - Bird, R. A1 - Brose, Robert A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Cerruti, M. A1 - Connolly, M. P. A1 - Cui, W. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Grube, J. A1 - Huetten, M. A1 - Hanna, D. A1 - Hervet, O. A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McArthur, S. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Petrashyk, A. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rulten, C. A1 - Sadeh, I. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tyler, J. A1 - Vassiliev, V. V. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Wilcox, P. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. T1 - Discovery of Very-high-energy Emission from RGB J2243+203 and Derivation of Its Redshift Upper Limit JF - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series N2 - Very-high-energy (VHE; > 100 GeV) gamma-ray emission from the blazar RGB J2243+203 was discovered with the VERITAS Cherenkov telescope array, during the period between 2014 December 21 and 24. The VERITAS energy spectrum from this source can be fitted by a power law with a photon index of 4.6 +/- 0.5, and a flux normalization at 0.15 TeV of (6.3 +/- 1.1) x 10(-10) cm(-2) s(-1) TeV-1. The integrated Fermi-LAT flux from 1 to 100 GeV during the VERITAS detection is (4.1 +/- 0.8) x 10(-8) cm(-2) s(-1), which is an order of magnitude larger than the four-year-averaged flux in the same energy range reported in the 3FGL catalog, (4.0 +/- 0.1 x 10(-9) cm(-2) s(-1)). The detection with VERITAS triggered observations in the X-ray band with the Swift-XRT. However, due to scheduling constraints Swift-XRT observations were performed 67 hr after the VERITAS detection, rather than simultaneously with the VERITAS observations. The observed X-ray energy spectrum between 2 and 10 keV can be fitted with a power law with a spectral index of 2.7 +/- 0.2, and the integrated photon flux in the same energy band is (3.6 +/- 0.6) x 10(-13) cm(-2) s(-1). EBL-model-dependent upper limits of the blazar redshift have been derived. Depending on the EBL model used, the upper limit varies in the range from z < 0.9 to z < 1.1. KW - galaxies: individual (RGB J2243+203) Y1 - 2017 U6 - https://doi.org/10.3847/1538-4365/aa8d76 SN - 0067-0049 SN - 1538-4365 VL - 233 SP - 1188 EP - 1204 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Archer, A. A1 - Benbow, W. A1 - Bird, R. A1 - Brose, Robert A1 - Buchovecky, M. A1 - Bugaev, V. A1 - Connolly, M. P. A1 - Cui, W. A1 - Daniel, M. K. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Hanna, D. A1 - Hervet, O. A1 - Holder, J. A1 - Hughes, G. A1 - Humensky, T. B. A1 - Hutten, M. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kelley-Hoskins, N. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McArthur, S. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Petrashyk, A. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rulten, C. A1 - Sadeh, I. A1 - Tyler, J. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Wilcox, P. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Wissel, S. A. A1 - Zitzer, B. T1 - Measurement of the iron spectrum in cosmic rays by VERITAS JF - Physical review : D, Particles, fields, gravitation, and cosmology N2 - We present a new measurement of the energy spectrum of iron nuclei in cosmic rays from 20 TeV to 500 TeV; The measurement makes use of a template-based analysis method, which, for the first time, is applied to the energy reconstruction of iron-induced air showers recorded by the VERITAS array of imaging atmospheric Cherenkov telescopes. The event selection makes use of the direct Cherenkov light which is emitted by charged particles before the first interaction, as well as other parameters related to the shape of the recorded air shower images. The measured spectrum is well described by a power law dF/dE = f(0) center dot (E/E-0)(-gamma) over the full energy range, with gamma = 2.82 +/- 0.30(stat)(-0.27)(+0.24)(syst) and f(0) = (4.82 +/- 0.98(stat)(-2.70)(+2.12)(syst)) x 10(-7) m(-2) s(-1) TeV-1 sr(-1) at E-0 = 50 TeV, with no indication of a cutoff or spectral break. The measured differential flux is compatible with previous results, with improved statistical uncertainty at the highest energies. Y1 - 2018 U6 - https://doi.org/10.1103/PhysRevD.98.022009 SN - 2470-0010 SN - 2470-0029 VL - 98 IS - 2 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Abeysekara, A. U. A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, Wystan A1 - Bird, Ralph A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cerruti, M. A1 - Chen, X. A1 - Ciupik, L. A1 - Cui, W. A1 - Dickinson, H. J. A1 - Eisch, J. D. A1 - Errando, M. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Grube, J. A1 - Hutten, M. A1 - Hakansson, N. A1 - Hanna, D. A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nguyen, T. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Pelassa, V. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rulten, C. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Fegan, S. A1 - Giebels, B. A1 - Horan, D. A1 - Berdyugin, A. A1 - Kuan, J. A1 - Lindfors, E. A1 - Nilsson, K. A1 - Oksanen, A. A1 - Prokoph, H. A1 - Reinthal, R. A1 - Takalo, L. A1 - Zefi, F. T1 - A Luminous and Isolated Gamma-Ray Flare from the Blazar B2 1215+30 JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - B2 1215+30 is a BL-Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes and subsequently confirmed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory with data collected between 2009 and 2012. In 2014 February 08, VERITAS detected a large-amplitude flare from B2. 1215+30 during routine monitoring observations of the blazar 1ES. 1218+304, located in the same field of view. The TeV flux reached 2.4 times the Crab Nebula flux with a variability timescale of <3.6 hr. Multiwavelength observations with Fermi-LAT, Swift, and the Tuorla Observatory revealed a correlated high GeV flux state and no significant optical counterpart to the flare, with a spectral energy distribution where the gamma-ray luminosity exceeds the synchrotron luminosity. When interpreted in the framework of a onezone leptonic model, the observed emission implies a high degree of beaming, with Doppler factor delta > 10, and an electron population with spectral index p < 2.3. KW - BL Lacertae objects: individual (B2 1215+30, VER J1217+301) KW - galaxies: active KW - galaxies: jets KW - galaxies: nuclei KW - gamma rays: galaxies Y1 - 2017 U6 - https://doi.org/10.3847/1538-4357/836/2/205 SN - 0004-637X SN - 1538-4357 VL - 836 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, Wystan A1 - Bird, Ralph A1 - Bourbeau, E. A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Cerruti, M. A1 - Connolly, M. P. A1 - Cui, W. A1 - Dwarkadas, Vikram V. A1 - Errando, M. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortson, L. A1 - Furniss, A. A1 - Griffin, S. A1 - Huetten, M. A1 - Hanna, D. A1 - Holder, J. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Kumar, S. A1 - Lang, M. J. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, Nahee A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Sadeh, I. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Slane, P. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Trepanier, S. A1 - Tyler, J. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Weisgarber, T. A1 - Wilcox, P. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. T1 - Gamma-ray Observations of Tycho's Supernova Remnant with VERITAS and Fermi JF - The astrophysical journal : an international review of spectroscopy and astronomical physics KW - material KW - data behind figure Y1 - 2017 U6 - https://doi.org/10.3847/1538-4357/836/1/23 SN - 0004-637X SN - 1538-4357 VL - 836 IS - 1 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Abeysekara, A. U. A1 - Archer, A. A1 - Aune, Taylor A1 - Benbow, Wystan A1 - Bird, Ralph A1 - Brose, Robert A1 - Buchovecky, M. A1 - Bugaev, V. A1 - Cui, Wei A1 - Daniel, M. K. A1 - Falcone, A. A1 - Feng, Qi A1 - Finley, John P. A1 - Fleischhack, H. A1 - Flinders, A. A1 - Fortson, L. A1 - Furniss, Amy A1 - Gotthelf, Eric V. A1 - Grube, J. A1 - Hanna, David A1 - Hervet, O. A1 - Holder, J. A1 - Huang, K. A1 - Hughes, G. A1 - Humensky, T. B. A1 - Huetten, M. A1 - Johnson, Caitlin A. A1 - Kaaret, Philip A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, David A1 - Krause, Maria A1 - Kumar, S. A1 - Lang, M. J. A1 - Lin, T. T. Y. A1 - Maier, Gernot A1 - McArthur, S. A1 - Moriarty, P. A1 - Mukherjee, Reshmi A1 - Ong, R. A. A1 - Otte, Adam Nepomuk A1 - Pandel, Dirk A1 - Park, Nahee A1 - Petrashyk, A. A1 - Pohl, Martin A1 - Popkow, Alexis A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Reynolds, P. T. A1 - Richards, Gregory T. A1 - Roache, E. A1 - Rousselle, J. A1 - Rulten, C. A1 - Sadeh, I. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, Karlen A1 - Tyler, J. A1 - Vassiliev, V. V. A1 - Wakely, S. P. A1 - Ward, J. E. A1 - Weinstein, A. A1 - Wells, R. M. A1 - Wilcox, P. A1 - Wilhelm, Alina A1 - Williams, David A. A1 - Zitzer, B. T1 - A Very High Energy gamma-Ray Survey toward the Cygnus Region of the Galaxy JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - 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. KW - acceleration of particles KW - cosmic rays KW - gamma rays: general KW - ISM: supernova remnants Y1 - 2018 U6 - https://doi.org/10.3847/1538-4357/aac4a2 SN - 0004-637X SN - 1538-4357 VL - 861 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Aliu, E. A1 - Archambault, S. A1 - Aune, T. A1 - Behera, B. A1 - Beilicke, M. A1 - Benbow, W. A1 - Berger, K. A1 - Bird, R. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Collins-Hughes, E. A1 - Connolly, M. P. A1 - Cui, W. A1 - Dumm, J. A1 - Dwarkadas, Vikram V. A1 - Errando, M. A1 - Falcone, A. A1 - Federici, Simone A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Galante, N. A1 - Gall, D. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Griffiths, S. T. A1 - Grube, J. A1 - Gyuk, G. A1 - Hanna, D. A1 - Holder, J. A1 - Hughes, G. A1 - Humensky, T. B. A1 - Kaaret, P. A1 - Kertzman, M. A1 - Khassen, Y. A1 - Kieda, D. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Madhavan, A. S. A1 - Maier, G. A1 - McCann, A. J. A1 - Meagher, K. A1 - Millis, J. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Pandel, D. A1 - Park, N. A1 - Pohl, Martin A1 - Popkow, A. A1 - Prokoph, H. A1 - Quinn, J. A1 - Ragan, K. A1 - Rajotte, J. A1 - Ratliff, G. A1 - Reyes, L. C. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rousselle, J. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Sheidaei, F. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tsurusaki, K. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Varlotta, A. A1 - Vassiliev, V. V. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Ward, J. E. A1 - Weinstein, A. A1 - Welsing, R. A1 - Wilhelm, Alina T1 - Investigating the TeV morpholoy of MGRO J1908+06 with veritas JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10(stat) +/- 0.20(sys). The TeV emission is extended, covering the region near PSR J1907+0602 and also extending toward SNR G40.5-0.5. When fitted with a two-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma(src) = 0 degrees.44 +/- 0 degrees.02. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5-0.5, 0 degrees.33 away. KW - gamma rays: general KW - gamma-ray burst: individual (MGRO J1908+06, VER J1907+062) KW - pulsars: individual (PSR J1907+0602) KW - ISM: supernova remnants Y1 - 2014 U6 - https://doi.org/10.1088/0004-637X/787/2/166 SN - 0004-637X SN - 1538-4357 VL - 787 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Abeysekara, A. U. A1 - Archambault, S. A1 - Archer, A. A1 - Benbow, W. A1 - Bird, R. A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Byrum, K. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Christiansen, J. L. A1 - Ciupik, L. A1 - Cui, W. A1 - Dickinson, H. J. A1 - Eisch, J. D. A1 - Errando, M. A1 - Falcone, A. A1 - Fegan, D. J. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Fortin, P. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Grube, J. A1 - Gyuk, G. A1 - Huetten, M. A1 - Hakansson, Nils A1 - Hanna, D. A1 - Holder, J. A1 - Humensky, T. B. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - Lin, T. T. Y. A1 - Maier, G. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Otte, A. N. A1 - Park, N. A1 - Perkins, J. S. A1 - Petrashyk, A. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Ratliff, G. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Vincent, S. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Williams, D. A. A1 - Zitzer, B. T1 - A SEARCH FOR BRIEF OPTICAL FLASHES ASSOCIATED WITH THE SETI TARGET KIC 8462852 JF - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters N2 - The F-type star KIC. 8462852 has recently been identified as an exceptional target for search for extraterrestrial intelligence (SETI) observations. We describe an analysis methodology for optical SETI, which we have used to analyze nine hours of serendipitous archival observations of KIC. 8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately 1 photon m(-2), is found. We also discuss the potential use of imaging atmospheric Cherenkov telescope arrays in searching for extremely short duration optical transients in general. KW - astrobiology KW - extraterrestrial intelligence KW - methods: observational KW - stars: individual ( KIC 8462852) KW - techniques: photometric Y1 - 2016 U6 - https://doi.org/10.3847/2041-8205/818/2/L33 SN - 2041-8205 SN - 2041-8213 VL - 818 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Archer, A. A1 - Benbow, W. A1 - Bird, R. A1 - Buchovecky, M. A1 - Buckley, J. H. A1 - Bugaev, V. A1 - Byrum, K. A1 - Cardenzana, J. V. A1 - Cerruti, M. A1 - Chen, Xuhui A1 - Ciupik, L. A1 - Collins-Hughes, E. A1 - Connolly, M. P. A1 - Eisch, J. D. A1 - Falcone, A. A1 - Feng, Q. A1 - Finley, J. P. A1 - Fleischhack, H. A1 - Flinders, A. A1 - Fortson, L. A1 - Furniss, A. A1 - Gillanders, G. H. A1 - Griffin, S. A1 - Grube, J. A1 - Gyuk, G. A1 - Hakansson, Nils A1 - Hanna, D. A1 - Holder, J. A1 - Humensky, T. B. A1 - Huetten, M. A1 - Johnson, C. A. A1 - Kaaret, P. A1 - Kar, P. A1 - Kelley-Hoskins, N. A1 - Kertzman, M. A1 - Kieda, D. A1 - Krause, M. A1 - Krennrich, F. A1 - Kumar, S. A1 - Lang, M. J. A1 - McArthur, S. A1 - McCann, A. A1 - Meagher, K. A1 - Millis, J. A1 - Moriarty, P. A1 - Mukherjee, R. A1 - Nieto, D. A1 - Ong, R. A. A1 - Park, N. A1 - Pelassa, V. A1 - Pohl, Martin A1 - Popkow, A. A1 - Pueschel, Elisa A1 - Quinn, J. A1 - Ragan, K. A1 - Ratliff, G. A1 - Reynolds, P. T. A1 - Richards, G. T. A1 - Roache, E. A1 - Rousselle, J. A1 - Santander, M. A1 - Sembroski, G. H. A1 - Shahinyan, K. A1 - Smith, A. W. A1 - Staszak, D. A1 - Telezhinsky, Igor O. A1 - Tucci, J. V. A1 - Tyler, J. A1 - Vassiliev, V. V. A1 - Wakely, S. P. A1 - Weiner, O. M. A1 - Weinstein, A. A1 - Wilhelm, Alina A1 - Williams, D. A. A1 - Zitzer, B. A1 - Yusef-Zadeh, F. T1 - TEV GAMMA-RAY OBSERVATIONS OF THE GALACTIC CENTER RIDGE BY VERITAS JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - 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. KW - Galaxy: center KW - gamma rays: general KW - supernovae: individual (G0.9+0.1) Y1 - 2016 U6 - https://doi.org/10.3847/0004-637X/821/2/129 SN - 0004-637X SN - 1538-4357 VL - 821 SP - 162 EP - 167 PB - IOP Publ. Ltd. CY - Bristol ER -