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  - 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  - 
TY  - JOUR
A1  - Allen, C.
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, W.
A1  - Bird, R.
A1  - Bourbeau, E.
A1  - Brose, Robert
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Cardenzana, J. V.
A1  - Cerruti, M.
A1  - Chen, Xuhui
A1  - Christiansen, J. L.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Daniel, M. K.
A1  - Eisch, J. D.
A1  - Falcone, Abe
A1  - Feng, Q.
A1  - Fernandez-Alonso, M.
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  - Huetten, M.
A1  - Hakansson, N.
A1  - Hanna, D.
A1  - Hervet, O.
A1  - Holder, J.
A1  - Hughes, G.
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  - Petrashyk, A.
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  - Rulten, C.
A1  - Sadeh, I.
A1  - Santander, Marcos
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Telezhinsky, Igor O.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
T1  - Very-High-Energy gamma-Ray Observations of the Blazar 1ES 2344+514 with VERITAS
JF  - Monthly notices of the Royal Astronomical Society
N2  - We present very-high-energy gamma-ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above the background of 20.8 sigma in 47.2 h (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations, the temporal properties of 1ES 2344+514 are studied on short and long times-scales. We fit a constant-flux model to nightly and seasonally binned light curves and apply a fractional variability test to determine the stability of the source on different time-scales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly binned light curves and for the long-term seasonally binned light curve at the > 3 sigma level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (x(2)/NDF = 7.89/6) by a power-law function with an index Gamma = 2.46 +/- 0.06(stat) +/- 0.20(sys) and extends to at least 8 TeV. The extragalactic-backgroundlight-deabsorbed spectrum is adequately fit (x(2)/NDF = 6.73/6) by a power-law function with an index Gamma = 2.15 +/- 0.06(stat) +/- 0.20(sys) while an F-test indicates that the power law with an exponential cut-off function provides a marginally better fit (x(2)/NDF = 2.56/5) at the 2.1 sigma level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source.
KW  - astroparticle physics
KW  - BL Lacertae objects: individual: 1ES 2344+514=VERJ2347+517
KW  - gamma-rays: galaxies
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx1756
SN  - 0035-8711
SN  - 1365-2966
VL  - 471
SP  - 2117
EP  - 2123
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Cerruti, M.
A1  - Benbow, W.
A1  - Chen, Xu
A1  - Dumm, J. P.
A1  - Fortson, L. F.
A1  - Shahinyan, K.
T1  - Luminous and high-frequency peaked blazars: the origin of the gamma-ray emission from PKS 1424+240
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. The current generation of ground-based Cherenkov telescopes, together with the LAT instrument on-board the Fermi satellite, have greatly increased our knowledge of gamma-ray blazars. Among them, the high-frequency-peaked BL Lacertae object (HBL) PKS 1424+240 (z similar or equal to 0.6) is the farthest persistent emitter of very-high-energy (VHE; E >= 100 GeV) gamma-ray photons. Current emission models can satisfactorily reproduce typical blazar emission assuming that the dominant emission process is synchrotron-self-Compton (SSC) in HBLs; and external-inverse-Compton (EIC) in low-frequency-peaked BL Lacertae objects and flat-spectrum-radio-quasars. Alternatively, hadronic models are also able to correctly reproduce the gamma-ray emission from blazars, although they are in general disfavored for bright quasars and rapid flares. Aims. The blazar PKS 1424+240 is a rare example of a luminous HBL, and we aim to determine which is the emission process most likely responsible for its gamma-ray emission. This will impact more generally our comprehension of blazar emission models, and how they are related to the luminosity of the source and the peak frequency of the spectral energy distribution. Methods. We have investigated different blazar emission models applied to the spectral energy distribution of PKS 1424+240. Among leptonic models, we study a one-zone SSC model (including a systematic study of the parameter space), a two-zone SSC model, and an EIC model. We then investigated a blazar hadronic model, and finally a scenario in which the gamma-ray emission is associated with cascades in the line-of-sight produced by cosmic rays from the source. Results. After a systematic study of the parameter space of the one-zone SSC model, we conclude that this scenario is not compatible with gamma-ray observations of PKS 1424+240. A two-zone SSC scenario can alleviate this issue, as well as an EIC solution. For the latter, the external photon field is assumed to be the infra-red radiation from the dusty torus, otherwise the VHE gamma-ray emission would have been significantly absorbed. Alternatively, hadronic models can satisfactorily reproduce the gamma-ray emission from PKS 1424+240, both as in-source emission and as cascade emission.
KW  - relativistic processes
KW  - BL Lacertae objects: general
KW  - BL Lacertae objects: individual: PKS 1424+240
KW  - astroparticle physics
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201730799
SN  - 1432-0746
VL  - 606
SP  - 35411
EP  - 35418
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Archer, A.
A1  - Benbow, Wystan
A1  - Bird, Ralph
A1  - Brose, Robert
A1  - Buchovecky, M.
A1  - Bugaev, V
A1  - Cui, Wei
A1  - Danie, M. K.
A1  - Falcone, A.
A1  - Feng, Qi
A1  - Finley, John P.
A1  - Flinders, A.
A1  - Fortson, L.
A1  - Furniss, Amy
A1  - Gillanders, Gerard H.
A1  - Huttens, M.
A1  - Hanna, David
A1  - Hervet, O.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Johnson, Caitlin A.
A1  - Kaaret, Philip
A1  - Kar, P.
A1  - Kelley-Hoskins, N.
A1  - Kieda, David
A1  - Krause, Maria
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Lin, T. T. Y.
A1  - McArthur, S.
A1  - Moriarty, P.
A1  - Mukherjee, Reshmi
A1  - Nieto, Daniel
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, Nahee
A1  - Petrashyk, A.
A1  - Pohl, Martin
A1  - Popkow, Alexis
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynold, P. T.
A1  - Richards, Gregory T.
A1  - Roache, E.
A1  - Rulten, C.
A1  - Sadeh, I
A1  - Sembroski, G. H.
A1  - Shahinyan, Karlen
A1  - Tyler, J.
A1  - Wakely, S. P.
A1  - Weiner, O. M.
A1  - Weinstein, A.
A1  - Wells, R. M.
A1  - Wilcox, P.
A1  - Wilhelm, Alina
A1  - Williams, David A.
A1  - Brisken, W. F.
A1  - Pontrelli, P.
T1  - HESS J1943+213
BT  - An extreme blazar shining through the galactic plane
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - HESS J1943+213 is a very high energy (VHE; > 100 GeV) gamma-ray source in the direction of the Galactic plane. Studies exploring the classification of the source are converging toward its identification as an extreme synchrotron BL Lac object. Here we present 38 hr of VERITAS observations of HESS J1943+213 taken over 2 yr. The source is detected with a significance of similar to 20 standard deviations, showing a remarkably stable flux and spectrum in VHE gamma-rays. Multifrequency Very Long Baseline Array (VLBA) observations of the source confirm the extended, jet-like structure previously found in the 1.6 GHz band with the European VLBI Network and detect this component in the 4.6 and 7.3 GHz bands. The radio spectral indices of the core and the jet and the level of polarization derived from the VLBA observations are in a range typical for blazars. Data from VERITAS, Fermi-LAT, Swift-XRT, the FLWO 48 ' telescope, and archival infrared and hard X-ray observations are used to construct and model the spectral energy distribution (SED) of the source with a synchrotron self-Compton model. The well-measured gamma-ray peak of the SED with VERITAS and Fermi-LAT provides constraining upper limits on the source redshift. Possible contribution of secondary gamma-rays from ultra-high-energy cosmic-ray-initiated electromagnetic cascades to the gamma-ray emission is explored, finding that only a segment of the VHE spectrum can be accommodated with this process. A variability search is performed across X-ray and gamma-ray bands. No statistically significant flux or spectral variability is detected.
KW  - astroparticle physics
KW  - BL Lacertae objects: individual (HESS J1943+213, VER J1943+213)
KW  - galaxies: active
KW  - galaxies: jets
KW  - galaxies: nuclei
KW  - gamma rays: galaxies
Y1  - 2018
U6  - https://doi.org/10.3847/1538-4357/aacbd0
SN  - 0004-637X
SN  - 1538-4357
VL  - 862
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Acero, F.
A1  - Aloisio, R.
A1  - Amans, J.
A1  - Amato, Elena
A1  - Antonelli, L. A.
A1  - Aramo, C.
A1  - Armstrong, T.
A1  - Arqueros, F.
A1  - Asano, Katsuaki
A1  - Ashley, M.
A1  - Backes, M.
A1  - Balazs, C.
A1  - Balzer, A.
A1  - Bamba, Aya
A1  - Barkov, Maxim
A1  - Barrio, J. A.
A1  - Benbow, Wystan
A1  - Bernloehr, K.
A1  - Beshley, V.
A1  - Bigongiari, C.
A1  - Biland, A.
A1  - Bilinsky, A.
A1  - Bissaldi, Elisabetta
A1  - Biteau, J.
A1  - Blanch, O.
A1  - Blasi, P.
A1  - Blazek, J.
A1  - Boisson, C.
A1  - Bonanno, G.
A1  - Bonardi, A.
A1  - Bonavolonta, C.
A1  - Bonnoli, G.
A1  - Braiding, C.
A1  - Brau-Nogue, S.
A1  - Bregeon, J.
A1  - Brown, A. M.
A1  - Bugaev, V.
A1  - Bulgarelli, A.
A1  - Bulik, T.
A1  - Burton, Michael
A1  - Burtovoi, A.
A1  - Busetto, G.
A1  - Bottcher, M.
A1  - Cameron, R.
A1  - Capalbi, M.
A1  - Caproni, Anderson
A1  - Caraveo, P.
A1  - Carosi, R.
A1  - Cascone, E.
A1  - Cerruti, M.
A1  - Chaty, Sylvain
A1  - Chen, A.
A1  - Chen, X.
A1  - Chernyakova, M.
A1  - Chikawa, M.
A1  - Chudoba, J.
A1  - Cohen-Tanugi, J.
A1  - Colafrancesco, S.
A1  - Conforti, V.
A1  - Contreras, J. L.
A1  - Costa, A.
A1  - Cotter, G.
A1  - Covino, Stefano
A1  - Covone, G.
A1  - Cumani, P.
A1  - Cusumano, G.
A1  - Daniel, M.
A1  - Dazzi, F.
A1  - De Angelis, A.
A1  - De Cesare, G.
A1  - De Franco, A.
A1  - De Frondat, F.
A1  - Dal Pino, E. M. de Gouveia
A1  - De Lisio, C.
A1  - Lopez, R. de los Reyes
A1  - De Lotto, B.
A1  - de Naurois, M.
A1  - De Palma, F.
A1  - Del Santo, M.
A1  - Delgado, C.
A1  - della Volpe, D.
A1  - Di Girolamo, T.
A1  - Di Giulio, C.
A1  - Di Pierro, F.
A1  - Di Venere, L.
A1  - Doro, M.
A1  - Dournaux, J.
A1  - Dumas, D.
A1  - Dwarkadas, Vikram V.
A1  - Diaz, C.
A1  - Ebr, J.
A1  - Egberts, Kathrin
A1  - Einecke, S.
A1  - Elsaesser, D.
A1  - Eschbach, S.
A1  - Falceta-Goncalves, D.
A1  - Fasola, G.
A1  - Fedorova, E.
A1  - Fernandez-Barral, A.
A1  - Ferrand, Gilles
A1  - Fesquet, M.
A1  - Fiandrini, E.
A1  - Fiasson, A.
A1  - Filipovic, Miroslav D.
A1  - Fioretti, V.
A1  - Font, L.
A1  - Fontaine, Gilles
A1  - Franco, F. J.
A1  - Freixas Coromina, L.
A1  - Fujita, Yutaka
A1  - Fukui, Y.
A1  - Funk, S.
A1  - Forster, A.
A1  - Gadola, A.
A1  - Lopez, R. Garcia
A1  - Garczarczyk, M.
A1  - Giglietto, N.
A1  - Giordano, F.
A1  - Giuliani, A.
A1  - Glicenstein, J.
A1  - Gnatyk, R.
A1  - Goldoni, P.
A1  - Grabarczyk, T.
A1  - Graciani, R.
A1  - Graham, J.
A1  - Grandi, P.
A1  - Granot, Jonathan
A1  - Green, A. J.
A1  - Griffiths, S.
A1  - Gunji, S.
A1  - Hakobyan, H.
A1  - Hara, S.
A1  - Hassan, T.
A1  - Hayashida, M.
A1  - Heller, M.
A1  - Helo, J. C.
A1  - Hinton, J.
A1  - Hnatyk, B.
A1  - Huet, J.
A1  - Huetten, M.
A1  - Humensky, T. B.
A1  - Hussein, M.
A1  - Horandel, J.
A1  - Ikeno, Y.
A1  - Inada, T.
A1  - Inome, Y.
A1  - Inoue, S.
A1  - Inoue, T.
A1  - Inoue, Y.
A1  - Ioka, K.
A1  - Iori, Maurizio
A1  - Jacquemier, J.
A1  - Janecek, P.
A1  - Jankowsky, D.
A1  - Jung, I.
A1  - Kaaret, P.
A1  - Katagiri, H.
A1  - Kimeswenger, S.
A1  - Kimura, Shigeo S.
A1  - Knodlseder, J.
A1  - Koch, B.
A1  - Kocot, J.
A1  - Kohri, K.
A1  - Komin, N.
A1  - Konno, Y.
A1  - Kosack, K.
A1  - Koyama, S.
A1  - Kraus, Michaela
A1  - Kubo, Hidetoshi
A1  - Mezek, G. Kukec
A1  - Kushida, J.
A1  - La Palombara, N.
A1  - Lalik, K.
A1  - Lamanna, G.
A1  - Landt, H.
A1  - Lapington, J.
A1  - Laporte, P.
A1  - Lee, S.
A1  - Lees, J.
A1  - Lefaucheur, J.
A1  - Lenain, J. -P.
A1  - Leto, Giuseppe
A1  - Lindfors, E.
A1  - Lohse, T.
A1  - Lombardi, S.
A1  - Longo, F.
A1  - Lopez, M.
A1  - Lucarelli, F.
A1  - Luque-Escamilla, Pedro Luis
A1  - Lopez-Coto, R.
A1  - Maccarone, M. C.
A1  - Maier, G.
A1  - Malaguti, G.
A1  - Mandat, D.
A1  - Maneva, G.
A1  - Mangano, S.
A1  - Marcowith, Alexandre
A1  - Marti, J.
A1  - Martinez, M.
A1  - Martinez, G.
A1  - Masuda, S.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Melioli, Claudio
A1  - Mineo, T.
A1  - Mirabal, N.
A1  - Mizuno, T.
A1  - Moderski, R.
A1  - Mohammed, M.
A1  - Montaruli, T.
A1  - Moralejo, A.
A1  - Mori, K.
A1  - Morlino, G.
A1  - Morselli, A.
A1  - Moulin, Emmanuel
A1  - Mukherjee, R.
A1  - Mundell, C.
A1  - Muraishi, H.
A1  - Murase, Kohta
A1  - Nagataki, Shigehiro
A1  - Nagayoshi, T.
A1  - Naito, T.
A1  - Nakajima, D.
A1  - Nakamori, T.
A1  - Nemmen, R.
A1  - Niemiec, Jacek
A1  - Nieto, D.
A1  - Nievas-Rosillo, M.
A1  - Nikolajuk, M.
A1  - Nishijima, K.
A1  - Noda, K.
A1  - Nogues, L.
A1  - Nosek, D.
A1  - Novosyadlyj, B.
A1  - Nozaki, S.
A1  - Ohira, Yutaka
A1  - Ohishi, M.
A1  - Ohm, S.
A1  - Okumura, A.
A1  - Ong, R. A.
A1  - Orito, R.
A1  - Orlati, A.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Padovani, Marco
A1  - Palacio, J.
A1  - Palatka, M.
A1  - Paredes, Josep M.
A1  - Pavy, S.
A1  - Persic, M.
A1  - Petrucci, P.
A1  - Petruk, Oleh
A1  - Pisarski, A.
A1  - Pohl, Martin
A1  - Porcelli, A.
A1  - Prandini, E.
A1  - Prast, J.
A1  - Principe, G.
A1  - Prouza, M.
A1  - Pueschel, Elisa
A1  - Puelhofer, G.
A1  - Quirrenbach, A.
A1  - Rameez, M.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - Ribo, M.
A1  - Rico, J.
A1  - Rizi, V.
A1  - Rodriguez, J.
A1  - Fernandez, G. Rodriguez
A1  - Rodriguez Vazquez, J. J.
A1  - Romano, Patrizia
A1  - Romeo, G.
A1  - Rosado, J.
A1  - Rousselle, J.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Sadeh, I.
A1  - Safi-Harb, S.
A1  - Saito, T.
A1  - Sakaki, N.
A1  - Sanchez, D.
A1  - Sangiorgi, P.
A1  - Sano, H.
A1  - Santander, M.
A1  - Sarkar, S.
A1  - Sawada, M.
A1  - Schioppa, E. J.
A1  - Schoorlemmer, H.
A1  - Schovanek, P.
A1  - Schussler, F.
A1  - Sergijenko, O.
A1  - Servillat, M.
A1  - Shalchi, A.
A1  - Shellard, R. C.
A1  - Siejkowski, H.
A1  - Sillanpaa, A.
A1  - Simone, D.
A1  - Sliusar, V.
A1  - Sol, H.
A1  - Stanic, S.
A1  - Starling, R.
A1  - Stawarz, L.
A1  - Stefanik, S.
A1  - Stephan, M.
A1  - Stolarczyk, T.
A1  - Szanecki, M.
A1  - Szepieniec, T.
A1  - Tagliaferri, G.
A1  - Tajima, H.
A1  - Takahashi, M.
A1  - Takeda, J.
A1  - Tanaka, M.
A1  - Tanaka, S.
A1  - Tejedor, L. A.
A1  - Telezhinsky, Igor O.
A1  - Temnikov, P.
A1  - Terada, Y.
A1  - Tescaro, D.
A1  - Teshima, M.
A1  - Testa, V.
A1  - Thoudam, S.
A1  - Tokanai, F.
A1  - Torres, D. F.
A1  - Torresi, E.
A1  - Tosti, G.
A1  - Townsley, C.
A1  - Travnicek, P.
A1  - Trichard, C.
A1  - Trifoglio, M.
A1  - Tsujimoto, S.
A1  - Vagelli, V.
A1  - Vallania, P.
A1  - Valore, L.
A1  - van Driel, W.
A1  - van Eldik, C.
A1  - Vandenbroucke, Justin
A1  - Vassiliev, V.
A1  - Vecchi, M.
A1  - Vercellone, Stefano
A1  - Vergani, S.
A1  - Vigorito, C.
A1  - Vorobiov, S.
A1  - Vrastil, M.
A1  - Vazquez Acosta, M. L.
A1  - Wagner, S. J.
A1  - Wagner, R.
A1  - Wakely, S. P.
A1  - Walter, R.
A1  - Ward, J. E.
A1  - Watson, J. J.
A1  - Weinstein, A.
A1  - White, M.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Wilcox, P.
A1  - Williams, D. A.
A1  - Wischnewski, R.
A1  - Wojcik, P.
A1  - Yamamoto, T.
A1  - Yamamoto, H.
A1  - Yamazaki, Ryo
A1  - Yanagita, S.
A1  - Yang, L.
A1  - Yoshida, T.
A1  - Yoshida, M.
A1  - Yoshiike, S.
A1  - Yoshikoshi, T.
A1  - Zacharias, M.
A1  - Zampieri, L.
A1  - Zanin, R.
A1  - Zavrtanik, M.
A1  - Zavrtanik, D.
A1  - Zdziarski, A.
A1  - Zech, Alraune
A1  - Zechlin, Hannes
A1  - Zhdanov, V.
A1  - Ziegler, A.
A1  - Zorn, J.
T1  - Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7-3946
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7-3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti) correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7-3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator.
KW  - cosmic rays
KW  - gamma rays: ISM
KW  - ISM: individual objects (RX J1713.7-3946, G347.3-0.5)
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/aa6d67
SN  - 0004-637X
SN  - 1538-4357
VL  - 840
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Aliu, E.
A1  - Archer, A.
A1  - Aune, T.
A1  - Barnacka, Anna
A1  - Behera, B.
A1  - Beilicke, M.
A1  - Benbow, W.
A1  - Berger, K.
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, Wei
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  - 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  - Kumar, S.
A1  - Lang, M. J.
A1  - Madhavan, A.
A1  - McArthur, S.
A1  - McCann, A.
A1  - Meagher, K.
A1  - Millis, J.
A1  - Moriarty, P.
A1  - Nieto, Daniel
A1  - Ong, R. A.
A1  - Orr, M.
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  - 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  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Zitzer, B.
T1  - Veritas observations of the BL LAC OBJECT PG 1553+113
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - 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%.
KW  - BL Lacertae objects: general
Y1  - 2015
U6  - https://doi.org/10.1088/0004-637X/799/1/7
SN  - 0004-637X
SN  - 1538-4357
VL  - 799
IS  - 1
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  - Benbow, Wystan
A1  - Bird, Ralph
A1  - Brantseg, T.
A1  - Brose, Robert
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Connolly, M. P.
A1  - Cui, Wei
A1  - Daniel, M. K.
A1  - Falcone, A.
A1  - Feng, Qi
A1  - Finley, John P.
A1  - Fortson, L.
A1  - Furniss, Amy
A1  - Gillanders, Gerard H.
A1  - Gunawardhana, Isuru
A1  - Huetten, M.
A1  - Hanna, David
A1  - Hervet, O.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Johnson, Caitlin A.
A1  - Kaaret, Philip
A1  - Kar, P.
A1  - Kertzman, M.
A1  - Krennrich, F.
A1  - Lang, M. J.
A1  - Lin, T. T. Y.
A1  - McArthur, S.
A1  - Moriarty, P.
A1  - Mukherjee, Reshmi
A1  - Ong, R. A.
A1  - Otte, Adam Nepomuk
A1  - Park, N.
A1  - Petrashyk, A.
A1  - Pohl, Martin
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, Gregory T.
A1  - Roache, E.
A1  - Rulten, C.
A1  - Sadeh, I.
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, Karlen
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Wells, R. M.
A1  - Wilcox, P.
A1  - Williams, D. A.
A1  - Zitzer, B.
A1  - Jorstad, Svetlana G.
A1  - Marscher, Alan P.
A1  - Lister, Matthew L.
A1  - Kovalev, Yuri Y.
A1  - Pushkarev, A. B.
A1  - Savolainen, Tuomas
A1  - Agudo, I.
A1  - Molina, S. N.
A1  - Gomez, J. L.
A1  - Larionov, Valeri M.
A1  - Borman, G. A.
A1  - Mokrushina, A. A.
A1  - Tornikoski, Merja
A1  - Lahteenmaki, A.
A1  - Chamani, W.
A1  - Enestam, S.
A1  - Kiehlmann, S.
A1  - Hovatta, Talvikki
A1  - Smith, P. S.
A1  - Pontrelli, P.
T1  - Multiwavelength Observations of the Blazar BL Lacertae
BT  - a new Fast TeV Gamma-Ray Flare
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - Combined with measurements made by very-long-baseline interferometry, the observations of fast TeV gamma-ray flares probe the structure and emission mechanism of blazar jets. However, only a handful of such flares have been detected to date, and only within the last few years have these flares been observed from lower-frequency-peaked BL. Lac objects and flat-spectrum radio quasars. We report on a fast TeV gamma-ray flare from the blazar BL. Lacertae observed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS). with a rise time of similar to 2.3 hr and a decay time of similar to 36 min. The peak flux above 200 GeV is (4.2 +/- 0.6) x 10(-6) photon m(-2) s(-1) measured with a 4-minute-binned light curve, corresponding to similar to 180% of the flux that is observed from the Crab Nebula above the same energy threshold. Variability contemporaneous with the TeV gamma-ray flare was observed in GeV gamma-ray, X-ray, and optical flux, as well as in optical and radio polarization. Additionally, a possible moving emission feature with superluminal apparent velocity was identified in Very Long Baseline Array observations at 43 GHz, potentially passing the radio core of the jet around the time of the gamma-ray flare. We discuss the constraints on the size, Lorentz factor, and location of the emitting region of the flare, and the interpretations with several theoretical models that invoke relativistic plasma passing stationary shocks.
KW  - BL Lacertae objects: individual (BL Lacertae = VER J2202+422)
KW  - galaxies: active
Y1  - 2018
U6  - https://doi.org/10.3847/1538-4357/aab35c
SN  - 0004-637X
SN  - 1538-4357
VL  - 856
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Abeysekara, A. U.
A1  - Archer, A.
A1  - Benbow, Wystan
A1  - Bird, Ralph
A1  - Brill, A.
A1  - Brose, Robert
A1  - Buchovecky, M.
A1  - Calderon-Madera, D.
A1  - Christiansen, J. L.
A1  - Cui, W.
A1  - Daniel, M. K.
A1  - Falcone, A.
A1  - Feng, Q.
A1  - Fernandez-Alonso, M.
A1  - Finley, J. P.
A1  - Fortson, Lucy
A1  - Furniss, Amy
A1  - Gent, A.
A1  - Giuri, C.
A1  - Gueta, O.
A1  - Hanna, David
A1  - Hassan, T.
A1  - Hervet, Oliver
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Johnson, Caitlin A.
A1  - Kaaret, P.
A1  - Kertzman, M.
A1  - Kieda, David
A1  - Krause, Maria
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Maier, Gernot
A1  - Moriarty, P.
A1  - Mukherjee, Reshmi
A1  - Nievas-Rosillo, M.
A1  - Ong, R. A.
A1  - Pfrang, Konstantin Johannes
A1  - Pohl, Martin
A1  - Prado, R. R.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Ribeiro, D.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rovero, A. C.
A1  - Sadeh, Iftach
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, Karlen
A1  - Sushch, Iurii
A1  - Svraka, T.
A1  - Weinstein, A.
A1  - Wells, R. M.
A1  - Wilcox, Patrick
A1  - Wilhelm, Alina
A1  - Williams, David Arnold
A1  - Williamson, T. J.
A1  - Zitzer, B.
T1  - Measurement of the Extragalactic Background Light Spectral Energy Distribution with VERITAS
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - The extragalactic background light (EBL), a diffuse photon field in the optical and infrared range, is a record of radiative processes over the universe?s history. Spectral measurements of blazars at very high energies (>100 GeV) enable the reconstruction of the spectral energy distribution (SED) of the EBL, as the blazar spectra are modified by redshift- and energy-dependent interactions of the gamma-ray photons with the EBL. The spectra of 14 VERITAS-detected blazars are included in a new measurement of the EBL SED that is independent of EBL SED models. The resulting SED covers an EBL wavelength range of 0.56?56 ?m, and is in good agreement with lower limits obtained by assuming that the EBL is entirely due to radiation from cataloged galaxies.
KW  - Extragalactic astronomy
KW  - Active galactic nuclei
KW  - Diffuse radiation
KW  - Cosmology
Y1  - 2019
U6  - https://doi.org/10.3847/1538-4357/ab4817
SN  - 0004-637X
SN  - 1538-4357
VL  - 885
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Benbow, W.
A1  - Bird, R.
A1  - Brill, A.
A1  - Brose, Robert
A1  - Chromey, A. J.
A1  - Daniel, M. K.
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Gillanders, G. H.
A1  - Giuri, C.
A1  - Gueta, O.
A1  - Hanna, D.
A1  - Halpern, J. P.
A1  - Hassan, Tarek
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Joyce, Amy M.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kelley-Hoskins, N.
A1  - Kertzman, M.
A1  - Kieda, D.
A1  - Krause, M.
A1  - Lang, M. J.
A1  - Lin, T. T. Y.
A1  - Maier, Gernot
A1  - Matthews, N.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - Nievas-Rosillos, M.
A1  - Ong, R. A.
A1  - Park, N.
A1  - Petrashyk, A.
A1  - Pohl, Martin
A1  - Pueschel, Elisa
A1  - Quinn, John
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rulten, C.
A1  - Sadeh, Iftach
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Sushch, Iurii
A1  - Wakely, S. P.
A1  - Wells, R. M.
A1  - Wilcox, P.
A1  - Wilhelm, Alina
A1  - Williams, David A.
A1  - Williamson, T. J.
T1  - Direct measurement of stellar angular diameters by the VERITAS Cherenkov telescopes
JF  - Nature astronomy
N2  - The angular size of a star is a critical factor in determining its basic properties1. Direct measurement of stellar angular diameters is difficult: at interstellar distances stars are generally too small to resolve by any individual imaging telescope. This fundamental limitation can be overcome by studying the diffraction pattern in the shadow cast when an asteroid occults a star2, but only when the photometric uncertainty is smaller than the noise added by atmospheric scintillation3. Atmospheric Cherenkov telescopes used for particle astrophysics observations have not generally been exploited for optical astronomy due to the modest optical quality of the mirror surface. However, their large mirror area makes them well suited for such high-time-resolution precision photometry measurements4. Here we report two occultations of stars observed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS)5 Cherenkov telescopes with millisecond sampling, from which we are able to provide a direct measurement of the occulted stars’ angular diameter at the ≤0.1 mas scale. This is a resolution never achieved before with optical measurements and represents an order of magnitude improvement over the equivalent lunar occultation method6. We compare the resulting stellar radius with empirically derived estimates from temperature and brightness measurements, confirming the latter can be biased for stars with ambiguous stellar classifications.
Y1  - 2019
U6  - https://doi.org/10.1038/s41550-019-0741-z
SN  - 2397-3366
VL  - 3
IS  - 6
SP  - 511
EP  - 516
PB  - Nature Publ. Group
CY  - London
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  -