H.E.S.S. Observations of PKS 2155-304

F. Aharonian; A. G. Akhperjanian; K.-M. Aye; A. R. Bazer-Bachi; M. Beilicke; W. Benbow; D. Berge; P. Berghaus; K. Bernlöhr; O. Bolz; C. Boisson; C. Borgmeier; F. Breitling; A. M. Brown; J. Bussons Gordo; P. M. Chadwick; V. R. Chitnis; L.-M. Chounet; R. Cornils; L. Costamante; B. Degrange; A. Djannati-Ataï; L. O'C. Drury; T. Ergin; P. Espigat; F. Feinstein; P. Fleury; G. Fontaine; S. Funk; Y. Gallant; B. Giebels; S. Gillessen; P. Goret; J. Guy; C. Hadjichristidis; M. Hauser; G. Heinzelmann; G. Henri; G. Hermann; J. A. Hinton; W. Hofmann; M. Holleran; D. Horns; O. C. de Jager; I. Jung; B. Khélifi; Nu. Komin; A. Konopelko; I. J. Latham; R. Le Gallou; M. Lemoine; A. Lemière; N. Leroy; T. Lohse; A. Marcowith; C. Masterson; T. J. L. Mccomb; M. de Naurois; S. J. Nolan; A. Noutsos; K. J. Orford; J. L. Osborne; M. Ouchrif; M. Panter; G. Pelletier; S. Pita; M. Pohl; G. Pühlhofer; M. Punch; B. C. Raubenheimer; M. Raue; J. Raux; S. M. Rayner; I. Redondo; A. Reimer; O. Reimer; J. Ripken; M. Rivoal; L. Rob; L. Rolland; G. Rowell; V. Sahakian; L. Saugé; S. Schlenker; R. Schlickeiser; C. Schuster; U. Schwanke; M. Siewert; H. Sol; R. Steenkamp; C. Stegmann; J.-P. Tavernet; C. G. Théoret; M. Tluczykont; D. J. van Der Walt; G. Vasileiadis; P. Vincent; B. Visser; H. J. Völk; S.J. Wagner

doi:10.1051/0004-6361:20041853

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H.E.S.S. Observations of PKS 2155-304

F. Aharonian, A. G. Akhperjanian, K.-M. Aye, A. R. Bazer-Bachi, M. Beilicke, W. Benbow, D. Berge, P. Berghaus, K. Bernlöhr, O. Bolz, …

Astronomy & Astrophysics - A&A, Vol.430, pp.865-875

2005

DOI: https://doi.org/10.1051/0004-6361:20041853

Abstract

The high-frequency peaked BL Lac PKS 2155-304 at redshift z=0.117 has been detected with high significance (~45 sigma) at energies greater than 160 GeV, using the H.E.S.S. stereoscopic array of imaging air-Cherenkov telescopes in Namibia. A strong signal is found in each of the data sets corresponding to the dark periods of July and October, 2002, and June-September, 2003. The observed flux of VHE gamma rays shows variability on time scales of months, days, and hours. The monthly-averaged integral flux above 300 GeV varies between 10% and 60% of the flux observed from the Crab Nebula. Energy spectra are measured for these individual periods of data taking and are characterized by a steep power law with a time-averaged photon index of 3.32 +/- 0.06. An improved chi-square per degree of freedom is found when either a power law with an exponential cutoff energy or a broken power law are fit to the time-averaged energy spectrum. However, the significance of the improvement is marginal (~2 sigma). The suggested presence of features in the energy spectrum may be intrinsic to the emission from the blazar, or an indication of absorption of TeV gamma rays by the extragalactic infrared background light.

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Title: H.E.S.S. Observations of PKS 2155-304
Creators - without role: F. Aharonian - Max Planck Innovation
A. G. Akhperjanian
K.-M. Aye - Durham University
A. R. Bazer-Bachi
M. Beilicke - Max Planck Society
W. Benbow - Max Planck Innovation
D. Berge - Max Planck Innovation
P. Berghaus - Collège de France
K. Bernlöhr - Max Planck Innovation
O. Bolz - Max Planck Innovation
C. Boisson - Centre de Gestion Scientifique
C. Borgmeier - Humboldt-Universität zu Berlin
F. Breitling - Humboldt-Universität zu Berlin
A. M. Brown
J. Bussons Gordo - Laboratoire de Physique Théorique
P. M. Chadwick
V. R. Chitnis - Laboratoire de Physique Nucléaire et de Hautes Énergies
L.-M. Chounet - Laboratoire Leprince-Ringuet
R. Cornils - Max Planck Innovation
L. Costamante - Max Planck Innovation
B. Degrange - Laboratoire d'Informatique de l'École Polytechnique
A. Djannati-Ataï - Physique Corpusculaire et Cosmologie
L. O'C. Drury
T. Ergin - Humboldt-Universität zu Berlin
P. Espigat - Collège de France
F. Feinstein - Max Planck Society
P. Fleury - Laboratoire d'Informatique de l'École Polytechnique
G. Fontaine - Laboratoire d'Informatique de l'École Polytechnique
S. Funk - Max Planck Innovation
Y. Gallant - Max Planck Society
B. Giebels - Laboratoire d'Informatique de l'École Polytechnique
S. Gillessen - Max Planck Innovation
P. Goret - DSM (Netherlands)
J. Guy - Centre de Gestion Scientifique
C. Hadjichristidis - Durham University
M. Hauser
G. Heinzelmann - Universität Hamburg
G. Henri - Université Joseph Fourier
G. Hermann - Max Planck Innovation
J. A. Hinton
W. Hofmann - Max Planck Innovation
M. Holleran - North-West University
D. Horns - Max Planck Innovation
O. C. de Jager
I. Jung - Max Planck Innovation
B. Khélifi - Max Planck Innovation
Nu. Komin - Humboldt-Universität zu Berlin
A. Konopelko - Max Planck Innovation
I. J. Latham
R. Le Gallou - Durham University
M. Lemoine - Laboratoire d'Informatique de l'École Polytechnique
A. Lemière - Collège de France
N. Leroy - Laboratoire d'Informatique de l'École Polytechnique
T. Lohse - Humboldt-Universität zu Berlin
A. Marcowith - Centre de Gestion Scientifique
C. Masterson - Max Planck Society
T. J. L. Mccomb
M. de Naurois - Max Planck Innovation
S. J. Nolan
A. Noutsos - Durham University
K. J. Orford
J. L. Osborne
M. Ouchrif - Centre de Gestion Scientifique
M. Panter - Max Planck Society
G. Pelletier - Université Joseph Fourier
S. Pita - Collège de France
M. Pohl - Ruhr University Bochum
G. Pühlhofer - Max Planck Innovation
M. Punch - Collège de France
B. C. Raubenheimer
M. Raue - Max Planck Society
J. Raux - Centre de Gestion Scientifique
S. M. Rayner
I. Redondo - Laboratoire d'Informatique de l'École Polytechnique
A. Reimer - Ruhr University Bochum
O. Reimer - Ruhr University Bochum
J. Ripken - Universität Hamburg
M. Rivoal - Centre de Gestion Scientifique
L. Rob - Charles University
L. Rolland - Centre de Gestion Scientifique
G. Rowell - Max Planck Innovation
V. Sahakian - A. Alikhanyan National Laboratory
L. Saugé - Max Planck Society
S. Schlenker - Humboldt-Universität zu Berlin
R. Schlickeiser - Ruhr University Bochum
C. Schuster - Ruhr University Bochum
U. Schwanke - Humboldt-Universität zu Berlin
M. Siewert - Ruhr University Bochum
H. Sol - Centre de Gestion Scientifique
R. Steenkamp - University of Namibia
C. Stegmann - Humboldt-Universität zu Berlin
J.-P. Tavernet - Laboratoire de Physique Nucléaire et de Hautes Énergies
C. G. Théoret - Physique Corpusculaire et Cosmologie
M. Tluczykont - Laboratoire d'Informatique de l'École Polytechnique
D. J. van Der Walt
G. Vasileiadis - Max Planck Innovation
P. Vincent - Centre de Gestion Scientifique
B. Visser - North-West University
H. J. Völk
S.J. Wagner - Max Planck Institute for Nuclear Physics
Publication Details: Astronomy & Astrophysics - A&A, Vol.430, pp.865-875
Identifiers: 9947122309311
Academic Unit: Université de Montpellier
Language: English
Resource Type: Journal article
Local Fields: in2p3-00023654