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J. S. Perkins,
H. M. Badran,
G Blaylock,
S. M. Bradbury,
P. Cogan,
Y. C. K. Chow,
W. Cui,
M. K. Daniel,
A. D. Falcone,
S. J. Fegan, [......],
K. Ragan,
P. F. Rebillot,
G. H. Sembroski,
D. Steele,
S. P. Swordy,
L. Valcarcel,
V. V. Vassiliev,
S. P. Wakely,
T. C. Weekes,
D A Williams
[show abstract]
[hide abstract]
ABSTRACT: Galaxy clusters might be sources of TeV gamma rays emitted by high-energy protons and electrons accelerated by large-scale structure formation shocks, galactic winds, or active galactic nuclei. Furthermore, gamma rays may be produced in dark matter particle annihilation processes at the cluster cores. We report on observations of the galaxy clusters Perseus and A2029 using the 10 m Whipple Cerenkov telescope during the 2003-2004 and 2004-2005 observing seasons. We apply a two-dimensional analysis technique to scrutinize the clusters for TeV emission. In this paper we first determine flux upper limits on TeVgamma- ray emission from point sources within the clusters. Second, we derive upper limits on the extended cluster emission. We subsequently compare the flux upper limits with EGRET upper limits at 100 MeV and theoretical models. Assuming that the gamma-ray surface brightness profile mimics that of the thermal X-ray emission and that the spectrum of cluster cosmic rays extends all the way from thermal energies to multi-TeV energies with a differential spectral index of similar to 2.1, our results imply that the cosmic-ray proton energy density is less than 7.9% of the thermal energy density for the Perseus Cluster.
The Astrophysical Journal 12/2008; · 6.02 Impact Factor
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A. Smith,
R. W. Atkins,
S. Bradbury,
O. Celik,
Y. C. K. Chow,
P. Cogan,
C. Dowdall,
S. J. Fegan,
P. Fortin,
D. Gall, [......],
K. Ragan,
G. H. Sembroski,
J. A. Toner,
L. Valcarcel,
V. V. Vassiliev,
R. G. Wagner,
S. P. Wakely,
T. C. Weekes,
R. J. White,
D. A. Williams
[show abstract]
[hide abstract]
ABSTRACT: In this paper we present the results of the past two years observations on the galactic microquasar LS I +61 303 with the
Whipple 10m gamma-ray telescope. The recent MAGIC detection of the source between 200GeV and 4TeV suggests that the source
is periodic with very high energy (VHE) gamma-ray emission linked to its orbital cycle. The entire 50-hour data set obtained
with Whipple from 2004 to 2006 was analyzed with no reliable detection resulting. The upper limits obtained in the 2005–2006
season covered several of the same epochs as the MAGIC Telescope detections, albeit with lower sensitivity. Upper limits are
placed on emission during the orbital phases of 0→0.1 and 0.8→1, phases which are not included in the MAGIC data set.
01/1970: pages 299-303;
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J. Kildea,
R. W. Atkins,
H. M. Badran,
G Blaylock,
I. H. Bond,
S. M. Bradbury,
J. H. Buckley,
D. A. Carter-Lewis,
O. Celik,
Y. C. K. Chow, [......],
M. Schroedter,
G. H. Sembroski,
A. W. Smith,
A. Syson,
J. A. Toner,
L. Valcarcel,
V. V. Vassiliev,
S. P. Wakely,
T. C. Weekes,
R. J. White
[show abstract]
[hide abstract]
ABSTRACT: Details are presented of the Whipple Observatory's 10 m atmospheric Cherenkov telescope and camera, as it evolved during the period 1997 until 2006. The design of the telescope and camera's optical and electronic systems is discussed together with a detailed description of the four-stage GRANITE (Gamma-RAy New Imaging TElescope) upgrade program, undertaken during the same time period. The objective of the upgrade was to improve the telescope's sensitivity for the detection of very-high-energy gamma-rays. Results from the program are provided and are briefly discussed in the context of the design of VERITAS. (C) 2007 Elsevier B.V. All rights reserved.
Physics Research Publications.
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A. Konopelko,
R. W. Atkins,
G Blaylock,
J. H. Buckley,
Y. Butt,
D. A. Carter-Lewis,
O. Celik,
P. Cogan,
Y. C. K. Chow,
W. Cui, [......],
S. P. Swordy,
J. A. Toner,
L. Valcarcel,
V. V. Vassiliev,
R. G. Wagner,
S. P. Wakely,
T. C. Weekes,
R. J. White,
D A Williams,
B. Zitzer
[show abstract]
[hide abstract]
ABSTRACT: We report on observations of the sky region around the unidentified TeV gamma-ray source (TeV J2032+ 4130) carried out with the Whipple Observatory 10 m atmospheric Cerenkov telescope for a total of 65.5 hr between 2003 and 2005. The standard two-dimensional analysis developed by the Whipple collaboration for a stand-alone telescope reveals an excess in the field of view at a pretrial significance level of 6.1 sigma. The measured position of this excess is alpha = 20(h)32(m)27(s), delta = 41 degrees 39'17" (J2000.0). The estimated integral flux for this gamma-ray source is about 8% of the Crab Nebula flux. The data are consistent with a pointlike source. Here we present a detailed description of the standard two-dimensional analysis technique used for the analysis of data taken with the Whipple Observatory 10 m telescope and the results for the TeV J2032+ 4130 campaign. We include a short discussion of the physical mechanisms that may be responsible for the observed gamma-ray emission, based on possible association with known astrophysical objects, in particular, Cygnus OB2.
Physics Research Publications.
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D. Horan,
R. W. Atkins,
H. M. Badran,
G Blaylock,
S. M. Bradbury,
J. H. Buckley,
K. L. Byrum,
O. Celik,
Y. C. K. Chow,
P. Cogan, [......],
D. Steele,
S. P. Swordy,
J. A. Toner,
L. Valcarcel,
V. V. Vassiliev,
R. G. Wagner,
S. P. Wakely,
T. C. Weekes,
R. J. White,
D A Williams
[show abstract]
[hide abstract]
ABSTRACT: Gamma-ray burst (GRB) observations at very high energies (VHE; E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and plerions, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. VHE emission coincident with delayed X-ray flare emission has also been predicted. GRB follow-up observations have had high priority in the observing program at the Whipple 10 m gamma-ray telescope, and GRBs will continue to be high-priority targets as the next-generation observatory, VERITAS, comes online. Upper limits on the VHE emission at late times (> similar to 4 hr) from seven GRBs observed with the Whipple Telescope are reported here.
Physics Research Publications.
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J. Holder,
R. W. Atkins,
H. M. Badran,
G Blaylock,
S. M. Bradbury,
J. H. Buckley,
K. L. Byrum,
D. A. Carter-Lewis,
O. Celik,
Y. C. K. Chow, [......],
S. P. Swordy,
A. Syson,
J. A. Toner,
L. Valcarcel,
V. V. Vassiliev,
S. P. Wakely,
T. C. Weekes,
R. J. White,
D A Williams,
R Wagner
[show abstract]
[hide abstract]
ABSTRACT: The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV gamma-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications. (c) 2006 Elsevier B.V. All rights reserved.
Physics Research Publications.
-
J. Holder,
R.W. Atkins,
H.M. Badran,
G. Blaylock,
S.M. Bradbury,
J.H. Buckley,
K.L. Byrum,
D.A. Carter-Lewis,
O. Celik,
Y.C.K. Chow, [......],
S.P. Swordy,
A. Syson,
J.A. Toner,
L. Valcarcel,
V.V. Vassiliev,
S.P. Wakely,
T.C. Weekes,
R.J. White,
D.A. Williams,
R. Wagner
[show abstract]
[hide abstract]
ABSTRACT: The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV γ-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications.
Astroparticle Physics.
-
J. Kildea,
R.W. Atkins,
H.M. Badran,
G. Blaylock,
I.H. Bond,
S.M. Bradbury,
J.H. Buckley,
D.A. Carter-Lewis,
O. Celik,
Y.C.K. Chow, [......],
M. Schroedter,
G.H. Sembroski,
A.W. Smith,
A. Syson,
J.A. Toner,
L. Valcarcel,
V.V. Vassiliev,
S.P. Wakely,
T.C. Weekes,
R.J. White
[show abstract]
[hide abstract]
ABSTRACT: Details are presented of the Whipple Observatory’s 10 m atmospheric Cherenkov telescope and camera, as it evolved during the period 1997 until 2006. The design of the telescope and camera’s optical and electronic systems is discussed together with a detailed description of the four-stage GRANITE (Gamma-RAy New Imaging TElescope) upgrade program, undertaken during the same time period. The objective of the upgrade was to improve the telescope’s sensitivity for the detection of very-high-energy gamma-rays. Results from the program are provided and are briefly discussed in the context of the design of VERITAS.
Astroparticle Physics.
