Ref HAL: in2p3-00024344_v1
Ref Arxiv: astro-ph/0505219
DOI: 10.1051/0004-6361:20053195
Ref. & Cit.: NASA ADS
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67 citations
Résumé:

The serendipitous discovery of an unidentified extended TeV $\gamma$-ray source close to the galactic plane named HESS J1303-631 at a significance of 21 standard deviations is reported. The observations were performed between February and June 2004 with the H.E.S.S. stereoscopic system of Cherenkov telescopes in Namibia. HESS J1303-631 was discovered roughly 0.6 \degres north of the binary system PSR B1259-63/SS 2883, the target object of the initial observation campaign which was also detected at TeV energies in the same field of view. HESS J1303-631 is extended with a width of an assumed intrinsic Gaussian emission profile of $\sigma$ = (0.16 $\pm$ 0.02)\degres and the integral flux above 380 GeV is compatible with constant emission over the entire observational period of (17$\pm$ 3)% of the Crab Nebula flux. The measured energy spectrum can be described by a power-law dN/dE $\sim$ E$^{-\Gamma}$ with a photon index of $\Gamma$ = 2.44 $\pm 0.05$_{stat} \pm$ 0.2$_{syst}$. Up to now, no counterpart at other wavelengths is identified. Various possible TeV production scenarios are discussed.

Ref HAL: in2p3-00025063_v1
DOI: 10.1016/j.nima.2005.08.056
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5 citations
Résumé:

The H.E.S.S experiment (for High Energy Stereoscopic System) consists of four imaging Cherenkov telescopes situated in the Namibia Khomas Highland desert (1800 m asl). Its main characteristics are the low energy threshold (100 GeV) and substantial flux sensitivity (1% Crab units). The combination of the four telescope data analysis provide good background rejection and angular resolution. Recent results on the performance and operation are reported here.

Commentaires: Proceedings of the fifth International Workshop on Ring Imaging Detectors

Ref HAL: in2p3-00023291_v1
Ref Arxiv: astro-ph/0411533
DOI: 10.1038/nature02960
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402 citations
Résumé:

A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7 - 3946 (G347.3 - 0.5), which was discovered by ROSAT in the X-ray spectrum and later claimed as a source of high-energy bold gamma-rays of TeV energies (1 TeV = 1012 eV). We present a TeV bold gamma-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks.

Ref HAL: in2p3-00025285_v1
Ref Arxiv: astro-ph/0406658
DOI: 10.1016/j.astropartphys.2004.06.006
Ref. & Cit.: NASA ADS
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105 citations
Résumé:

H.E.S.S.—the high energy stereoscopic system—is a new system of large atmospheric Cherenkov telescopes for GeV/TeV astronomy. Each of the four telescopes of 107 m2 mirror area is equipped with a 960-pixel photomultiplier-tube camera. This paper describes the methods used to convert the photomultiplier signals into the quantities needed for Cherenkov image analysis. Two independent calibration techniques have been applied in parallel to provide an estimation of uncertainties. Results on the long-term stability of the H.E.S.S. cameras are also presented.

Ref HAL: in2p3-00022258_v1
Ref Arxiv: astro-ph/0408145
DOI: 10.1051/0004-6361:200400055
Ref. & Cit.: NASA ADS
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342 citations
Résumé:

We report the detection of a point-like source of very high energy (VHE) gamma-rays coincident within 1' of Sgr A*, obtained with the H.E.S.S. array of Cherenkov telescopes. The gamma-rays exhibit a power-law energy spectrum with a spectral index of -2.2 +/- 0.09 +/- 0.15 and a flux above the 165 GeV threshold of (1.82 +/- 0.22) \times 10^{-7} m^{-2} s^{-1}. The measured flux and spectrum differ substantially from recent results reported in particular by the CANGAROO collaboration.