60 research outputs found
High Energy Gamma Rays
The Very High Energy Gamma Ray Astronomy (VHE) is a rapidly evolving branch
of modern astronomy, which covers the range from about 50 GeV to several tens
of TeV from the ground. In the past years, the second generation instruments
firmly established a growing and varied list of sources including plerions,
supernova remnants and active galactic nuclei, and started to study some
fundamental questions such as the origin of cosmic rays or the emission
mechanisms of the active galactic nuclei.
New results now include the first VHE unidentified sources as well as more
puzzling sources such as the Galactic center. The arrival of new generation
instruments (HESS, CANGAROO III, VERITAS, MAGIC) already gives a impressive
look at the near future. Here we attempt to summarize the current status of the
field. We briefly describe the instruments and analysis techniques, and give an
outlook on the sources detected sofar.Comment: Invited talk at the XXIV Physics in Collisions Conference (PIC04),
Boston, USA, June 2004, 10 pages, LaTeX, 13 eps figures. PSN TUET0
Analysis methods for Atmospheric Cerenkov Telescopes
Three different analysis techniques for Atmospheric Imaging System are presented. The classical Hillas parameters based technique is shown to be robust and efficient, but more elaborate techniques can improve the sensitivity of the analysis. A comparison of the different analysis techniques shows that they use different information for gamma-hadron separation, and that it is possible to combine their qualities
Observation of the microquasar LS 5039 with H.E.S.S.
texte intégral disponible sur http://proc.sf2a.asso.fr/2006/2006sf2a.conf..0125D.pdfInternational audienceThe High Energy Stereoscopic System (H.E.S.S) is an array of four imaging atmospheric-Cherenkov telescopes located in the Khomas Highlands of Namibia. The microquasar LS 5039 was serendipously detected by the instrument during the scan of the inner galactic plane in 2004. Deeper observation were carried out in 2005, and brought a clear evidence for TeV emission variability. This is after PSRB 1259-63 the second VHE gamma-rays variable galactic source discovered. We will present detailed studies of the source variability (flux and spectral shape) compared to other wavelengthes and shortly review the implications for the existing emission models
Utilisation de la grille EGI pour l'astrophysique de très hautes énergies avec H.E.S.S.
Utilisation de la grille EGI pour l'astrophysique de très hautes énergies avec H.E.S.S
Exploiting the time of arrival of Cherenkov photons at the 28 m H.E.S.S. telescope for background rejection: Methods and performance
In 2012, the High Energy Stereoscopic System (H.E.S.S.) was expanded by a
fifth telescope (CT5). With an effective mirror diameter of 28m, CT5 is able to
detect the Cherenkov light of very faint gamma-ray air showers, thereby
significantly lowering the energy threshold of this telescope compared to the
other four telescopes. Extracting as much information as possible from the
recorded shower image is crucial for background rejection and to reach an
energy threshold of a few tens of GeV. The camera of CT5 is conceived to
register the time of the charge pulse maximum with respect to the beginning of
the 16 ns integration window of each pixel. This information can be utilised to
improve the event reconstruction. It also helps to reduce the background
contamination at low energies. We present new techniques for background
rejection based on CT5 timing information and evaluate their performance
The Galactic Sky seen by H.E.S.S
The H.E.S.S. experiment is an array of four imaging Cherenkov telescopes
located in the Khomas Highlands of Namibia. It has been operating in its full
configuration since December 2003 and detects very-high-energy (VHE) gamma rays
ranging from 100 GeV to 50 TeV. Since 2004, the continuous observation of the
Galactic Plane by the H.E.S.S. array of telescopes has yielded the discovery of
more than 50 sources, belonging to the classes of pulsar wind nebulae (PWN),
supernova remnants (SNR), gamma ray binaries and, more recently, a stellar
cluster and molecular clouds in the vicinity of shell-type SNRs. Galactic
emission seen by H.E.S.S. and its implications for particle acceleration in our
Galaxy are discussed.Comment: Proceedings of COSPAR 2010 conference. Accepted for publication in
Advances in Space Research (special issue
Briefing Book for the Zeuthen Workshop
On Jun 18th 2004, the CERN Council, upon the initiative of its President, Prof. Enzo Iarocci, established an ad hoc scientific advisory group (the Strategy Group), to produce a draft strategy for European particle physics, which is to be considered by a special meeting of the CERN Council, to be held in Lisbon on Jul 14th 2006. There are three volumes to the Briefing Book. This first volume contains an introductory essay on particle physics, a summary of the issues discussed at the Open Symposium, and discussions of the other themes that the Strategy should address. The introductory essay on particle physics and the other themes were commissioned by the Preparatory Group. The summary of the issues discussed in the Symposium was prepared by the chairs of the sessions, the session speakers and the scientific secretaries. We acknowledge that this has been a difficult task, again on a very tight timescale, and we would like to thank all of those who have contributed to this volume
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