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Very high energy gamma-rays from the Galactic Centre measured by H.E.S.S.

Very high energy gamma-rays from the Galactic Centre measured by H.E.S.S. L. Rolland (CEA-Saclay/DSM/DAPNIA/SPP, Gif-sur-Yvette, France) for the H.E.S.S. collaboration. The H.E.S.S. detector The Galactic Centre Observations of the Galactic Centre with H.E.S.S. (rollandl@in2p3.fr).

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Very high energy gamma-rays from the Galactic Centre measured by H.E.S.S.

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  1. Very high energy gamma-raysfrom the Galactic Centremeasured by H.E.S.S. L. Rolland (CEA-Saclay/DSM/DAPNIA/SPP, Gif-sur-Yvette, France) for the H.E.S.S. collaboration The H.E.S.S. detector The Galactic Centre Observations of the Galactic Centre with H.E.S.S. (rollandl@in2p3.fr)

  2. The H.E.S.S. experiment

  3. Gamma-ray Cosmic ray Particle shower Gamma-ray candidate Cherenkov light muon hadron Imaging Atmopheric Cherenkov Telescopes Atmosphere = calorimeter Image of Cherenkov flashs (~3 ns)

  4. Gamma-ray Cosmic ramy Gamma-ray Cosmic ray Particle shower Particle shower Impact parameter of the gamma-ray Cherenkov light Cherenkov light 2 4  3 1 Stereoscopic system Rejection of isolated muons at trigger level Energy threshold decreased Hadronic rejection improved Gamma-ray reconstruction improved Source direction

  5. The H.E.S.S. experiment Site : Namibia, 23°16'' S, 16°30'' E, altitude 1800 m

  6. Real performances • Trigger rate ~ 400 Hz • Dead time ~ 10% • Field of view 5° • Threshold ~ 100 GeV at zenith • Angular resolution ~ 6' gerbe to gerbe • Energy resolution ~ 15% • Crab Nebula detection at zenith: • 0,01 Crabe : ~25 h • 0,05 Crabe : ~1 h • 0,10 Crabe : ~15 min • 1,00 Crabe : ~10 s

  7. The first sources seen by H.E.S.S. May 2005 16 galactic sources 4 extragalactic sources + ~5 galactic sources (1 microquasar) + ~4 extragalactic sources

  8. H.E.S.S

  9. H.E.S.S. Galactic survey (2004) Gal. Centre HESS J1804-216 HESS J1825-137 HESS J1837-069 HESS J1834-087 HESS J1813-178 G0.9+0.1 30° 0° LS 5039 HESS J1713-381 HESS J1702-420 HESS 1632-478 HESS J1745-303 HESS J1634-472 HESS J1708-410 330° 359° RX J1713.7-3946 HESS J1614-518 HESS J1640-485 HESS J1616-508 Sources > 6 sigma (9 new, 11 total) Sources > 4 sigma (7 new)

  10. Supernova remnants RXJ 1713- Excess map (number of g-rays) X-ray contours: ASCA

  11. Chandra, X Plerions MSH 15-52 Excess map (number of g-rays) X-ray contours: ROSAT

  12. Aharonian et al. Science (2005) New type of VHE sources: microquasar Microquasar: LS5039 First VHE detection of a microquasar Expect a strong attenuation in the photon field of the starEmission further away from compact objectJets (microblazar) ? Or other mechanism Variablility expected,needed to constrain the models (shorter time scaleas in blazars / orbital period) Being reobserved in 2005,already significant signal (16 sigma) 2005 data analysis under way H.E.S.S. Observations of LS 5039

  13. VHE unidentified sources Known (2003): TeV 2032 HEGRA Galactic CenterCANGAROO, Whipple, HESS, MAGIC New Sources (2005): J1303-631 HESS J1614-518HESS J1804-216, “ J1804-216 “ Unconfirmed: 3EG J0520+2556 Milagro [Dingus] IMAGES SOURCES HESS Is there are new population of “dark” TeV emitters ?? Extended, structured Power law energy spectrum, photon index ~2.2

  14. Source Type* 2003 2005 Pulsar Wind Nebula (e.g. Crab, MSH 15-52 …) 1 6 Supernova Remnants (e.g. Cas-A, RXJ 1713 …) 2 6 Binary Pulsar (B1259-63) 0 1 Micro-quasar (LS 5039) 0 1 Diffuse (Cygnus region, GC region) 0 2 AGN (e.g. Mkn 421, PKS 2155 …) 7 11 Unidentified 2 6 TOTAL 12 32 Gamma-ray source count (ICRC 2005) * Includes likely associations of HESS unid sources.  Explosion in the number of VHE sources.

  15. Pulsar Nebula AGN Other, UNID SNR The VHE sky - 1995 Mrk421 Mrk501 Crab R.A.Ong Aug 2005

  16. Pulsar Nebula AGN Other, UNID SNR The VHE sky - 2003 Mrk421 H1426 M87 Mrk501 1ES1959 RXJ 1713 Cas A GC TeV 2032 Crab 1ES 2344 PKS 2155 R.A.Ong Aug 2005

  17. Pulsar Nebula AGN Other, UNID SNR The VHE sky - 2005 + 8-15 add. sources in galactic plane. 1ES 1218 Mrk421 H1426 M87 Mrk501 PSR B1259 1ES 1101 1ES1959 SNR G0.9 RXJ 1713 RXJ 0852 Cas A LS 5039 GC Vela X TeV 2032 Crab 1ES 2344 HessJ1303 Cygnus Diffuse MSH 15-52 PKS 2155 H2356 PKS 2005 R.A.Ong Aug 2005

  18. The Galactic Centre

  19. VHE candidates at the Galactic Centre A supermassive black hole: Sgr A* 4° × 5°

  20. <1x1 pc 20 cm- VLA In the vicinity of the black hole A supernova remnant Sgr A East ~4x3 pc

  21. The GC seen by INTEGRAL 2° × 2° 20-40 keV 40-100 keV

  22. The 2004 signal: HESS J1745-290 48 hours live time from March 30 to September 4, 2004 • pointing within 2 degrees of Sgr A* • 0° to 60° zenith angle • <0.11° within Sgr A*: • 38  • 1862 

  23. A new plerion: G0.9+0.1 • G0.9+0.1 • mixte morphology type SNR • photon index ~2.3 • 3% Crabe flux

  24. HESS J1745-290 - Angular distribution Compatible with point-source in the very centre Tail at larger distance

  25. Diffuse emission • Assuming symmetric gaussian • distance to Sgr A* 3.9''±13''±20'' • extension: 1.9' ± 0.23' 20 cm- VLA HESS J1745-290 - Position and extension Assuming point-like source compatible with Sgr A* 5.6''±10''±20''

  26. Other high energy observations Compatibility with • INTEGRAL source (G1) • black hole Sgr A* • supernova Sgr A East Incompatibility with • unidentified EGRET source (99% CL)

  27. Energy range: 166 GeV-37 TeV Compatible with 2003 spectrum: =2.2±0.09±0.15 (>1TeV)=(2.0±0.4±0.3)x10-12 cm-2s-1 Search for exponential cut-off: Ecut > 6 TeV (95% CL) HESS J1745-290 - Spectrum 95% CL upper limits

  28. Night average flux 15% systematic errors added HESS J1745-290 - Light curves Fit light curve by a constant: 2 probability projection of the reduced flux

  29. HESS J1745-290 - Light curves 15% systematic errors added to every light curve points Light curves compatible with constant flux Sensitivity of the method for a 5  detection of a flare: nightly: x 2 28 minutes: x 4 10 minutes: x 7

  30. Astrophysical candidates

  31. Emission from Sgr A* • Sgr A* : supermassive black hole • variability • energy spectrum

  32. Emission from Sgr A East • Sgr A East :supernova remnant • extension • energy spectrum

  33. Emission from Sgr A East • Sgr A East : supernova remnant • extension • energy spectrum

  34. Other possibilities • Cosmic-ray interaction with dense medium • Collision of stellar winds • Other contributions: • transient sources observed in X-rays

  35. Dark matter at the Galactic Centre

  36. Halo density profiles Predictions Extrapolations Shape of the DM halo Large scale structure formation models

  37. mKK = 10 TeV Power law continuum MSSM Gamma-ray: DM annihilation flux • Predicted gamma-ray annihilation flux: Dark matter halo • WIMP nature • Neutralino annihilation • lines are loop suppressed • hadronisation (W± and Z0 ) • Kaluza-Klein annihilation • lines are loop suppressed • charged leptons and quarks Cut-off

  38. Gamma-ray: DM indirect detection • Predicted gamma-ray annihilation flux: Angular distribution Energy spectrum WIMP nature DM halo shape

  39. Diffuse emission BUT Only dark matter - Halo shape Angular distribution compatible with cuspy halo a ~ 1 Cherenkov telescopes constraints DM halo shape Point-like source: a > 1.2

  40. Only dark matter - Spectrum shape Different spectra than Bergström and Profumo Misuse of PYTHIA ? Different spectra between Dark Susy and PYTHIA ?

  41. Dark matter and astrophysical background • 2 composonant spectrum: • power law • DM annihilation • Shape of the halo: NFW Uncertainties in density > 106 Spectrum compatible with power law Upper limits on .v

  42. Dark matter and astrophysical background 99% CL upper limits

  43. Position compatible with Sgr A* within 6'' Slightly extended ? s = 1.8' 38 s detection of HESS J1745-290 in 2004 Uncurved power law spectrum G = 2.27 No indication of variability in 2003-2004 • Possible origin for the gamma-rays: • Sgr A* • Sgr A East • stellar wind collisions • cosmic-ray interactions in the dense medium • dark matter annihilations

  44. Pure DM annihilation spectrum incompatible with the data 38 s detection of HESS J1745-290 in 2004 Loose constraints on s.v in case of astrophysical background Looking for other DM source candidates: Sgr A Dwarf (25 kpc) Canis Major (8 kpc)

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