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Current Status of the HESS Gamma Ray Experiment. G.Vasileiadis LPTA-CNRS/IN2P3,Montpellier. HESS Collaboration. 3 continents 8 countries 19 institutions 69 physicists 100 engineers and technicians. MPI Kernphysik, Heidelberg Humboldt Univ. Berlin Ruhr-Univ. Bochum
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Current Status of the HESS Gamma Ray Experiment G.Vasileiadis LPTA-CNRS/IN2P3,Montpellier
HESS Collaboration 3 continents 8 countries 19 institutions 69 physicists 100 engineers and technicians MPI Kernphysik, Heidelberg Humboldt Univ. Berlin Ruhr-Univ. Bochum Univ. Hamburg Landessternwarte Heidelberg Univ. Kiel LLR, Ecole Polytechnique, Palaiseau PCC, College de France, Paris LPNHE-Paris, Univ. Paris VI-VII CEA Saclay CESR Toulouse LAOG Grenoble Observatoire de Paris LPTA, Montpellier Durham Univ. Charles Univ., PragYerewan Physics Inst. Dublin Inst. for Adv. Studies Univ. Namibia, Windhoek Univ. Potchefstroom Namibia (Gamsberg) /1800m Alt.
SNRs Pulsars and PWN Micro quasars X-ray binaries AGNs GRBs Origin of cosmic rays Space-time & relativity Dark matter Cosmology Scientific Objectives
Telescope • Mirror Dishes : 4 x 107 m2 • Diameter 12 m • Focal Length 15 m • Telescope Separation 120 m • Mirror : 380 x 60 circular facets • Ground Glass, Aluminized and Quartz coated • PSF 1.3’ / 0.38 mrad • Pointing Precision 8” • Field View 5o (1.4m) • Pixel Size 2.8 mrad • 960 Photomultipliers • Camera weight 900 kgr • 3-cable control to rest of system
Energy Threshold / Sensitivity 0.01 Crab in ~25 h 0.05 Crab in ~ 1 h 1.0 Crab in 30 ~sec
Angular Resolution Angular resolution ~ 0.1 degrees Point source location 30” to 2’ FOV : 3-4 degrees
Great success by HESSGalactic place survey HESS Galactic plane Survey Survey in 2-3% Crab unit Astro-ph/0510397 17 sources + Several PWNs Shell type SNRs X-Ray Binary (Microquasars) Un-ID sources
SNRs Vela Junior RX J1713
Energy Spectrum Profile Hard Spectrum from WHOLE SNR (H.E.S.S.) (cf. CANG spectrum for NW rim) dN/dE ~ E-2.19+/-0.1+/0.15 F(1-10TeV) ~ 3x10-11 erg/cm2/s (~1 Crab) Extends to 10 TeV --> 100 TeV particles Clouds (n~100 cm-3) NW region --> Ep ~ 1049/n erg --> 2004 data (>50h) ....spectral imaging, energy resolved morphology
PWN IC emission HESS HESS HESS HESS VelaX Kookaburra MSH 15-52 HESS J1825
Binary System LS 5039
Galactic Center Ridge Spectral index 2.29 ± 0.07 ± 0.20 Implies harder CR spectrum than in our solar system HESS MAGIC
Origin of VHE Signal • Black Hole Scenario • Shocks in Sgr A* accretion flow/wind • Proton radiation near SgrA* • Classic options : • Sgr A proton accelerator • Pulsar / PWN • Interaction of CR with moolecular clouds • Very hard to fit power-law-like data with models for DM annihilations... • Any DM signal is likely buried underneath an 'astrophysical' source (A*, Sgr A East, new PWN...)
Extragalactic sources New Sources
Future • Very Large Cherenkov Telescope • Reflector 28m diameter • Focal distance 35m • Camera: 2.5m diameter • 2048 PMTs (0.07o/pixel) • Fov : 3o • Trigger rate 2-20KHz • Fast analogue memories needed • Centre of Phase I array • Push threshold --> 10-20 GeV • Level 2 trigger. • Development underway
Summary • Now we know about 50 TeV sources in the sky. The physics in TeV gamma ray astronomy is very rich and still there are many open questions. • Stereoscopic mode of operation vital for background rejection . • Forthcoming HESS-II will bring energy threshold down to 50 Gev. • All sky observatory is ideal (north & south stations) • Multi-wavelength and multi-messenger observation are very important to understand the nature of high energy sources • GLAST, IceCube, KM3, Auger, etc..
By W.Hofmann ∝Ntel 50hrs ∝Area Background Limited Signal Limited