1. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier M. Vivier IRFU/SPP CEA-Saclay, France Indirect searches for Dark Matter with the H.E.S.S. high energy  -rays telescope array. 43 rd Rencontres de Moriond La Thuile (Val d'Aosta, Italy) March 15 - 22, 2008

2. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier ~ 30 institutes ~ 130 physicists & astrophysicists (mainly from France & Germany) MPI Kernphysik, HeidelbergLPTA Montpellier Humboldt Univ. BerlinIRFU Saclay Ruhr-Univ. BochumCESR Toulouse Univ. HamburgDurham Univ. LSW HeidelbergDublin Inst. for Adv. Studies Univ. TübingenCharles Univ., Prague Univ. ErlangenYerewan Physics Inst. Ecole Polytechnique, PalaiseauNorth-West Univ., Potchefstroom APC ParisUniv. of Namibia, Windhoek Univ. Paris VI-VIIN. Kopernicus Astr. Center, Warsaw Paris Observatory, MeudonJagiellonian University, Cracow LAPP AnnecyInstitute of Nuclear Physics, Warsaw LAOG GrenobleSpace research center, Warsaw High Energy Stereoscopic System An array of four imaging Cerenkov telescopes dedicated for VHE  -rays astronomy (E>100 GeV)

3. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier The 3rd generation Cerenkov telescopes in operation H.E.S.S.CANGAROO III MAGIC VERITAS

4. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier The H.E.S.S. telescope array - 4 telescopes in a square formation - 13 m diameter telescopes: mirror area of 107 m², camera of 960 PMTs covering a 5° FoV. - stereoscopic reconstruction - angular resolution < 0.1° - energy threshold ~ 100 GeV at zenith - sensitivity (5  ): 1% Crab flux in 25 hrs Located in Namibia, at 1800m above sea level. Scientific goals: Cosmic rays physics (SNR, AGN,...) & DM…

5. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Predictions for Dark Matter annihilation fluxes Particle Physics model - Neutralino annihilation (pMSSM scenarios)  -ray lines are loop suppressed continuum emission from hadronization of final states products (W ±, Z 0, quarks, mesons). - Kaluza-Klein annihilation (UED models)  -ray lines are loop suppressed continuum emission from charged leptons and quarks. Dark Matter mass distribution - obtained from numerical simulations or from observationnal data. - relatively large uncertainties in the inner part of the profiles (cusps or cores?)

6. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Potential targets for H.E.S.S. Targets with large DM concentration. Galactic Centre: - heliocentric distance: 8.5 kpc - standard  -ray emitters, important astrophysical background - diffuse emission along the galactic plane Galaxy clusters centres: -Virgo cluster (M 87), distance: 16.3 Mpc - Variable emission incompatible with DM Dwarf Spheroidal Galaxies: -4 observable by H.E.S.S. at less than 100kpc from the GC

7. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier The Galactic Centre (HESS J1745-290) − ~ 100 hours of data taking (2004→2006) − statistical significance of the excess at the target position ~ 60  − compatible with point-like source after subtraction of the diffuse emission (F. Aharonian et al., Nature 439 (2006) 695-698) Expected level of background events 2004 - 2006 ON source region

8. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Interpretations of the HESS J1745-290 signal SNR SgrA East (90 cm) − emission from SNR SgrA East? − vicinity of the Sgr A* black hole  correlation with X-ray/radio signal? (next slides) − interaction of protons or electrons with the ISM in central stellar cluster? − emission from PWN G359.94-0.04? − annihilations of WIMPs near GC ruled out (Aharonian et al, PRL, 97, 221102 (2006)) (next slides) − new preliminary result: l=359 ° 56’41.1’’± 6.4’’± 6’’ b=-0°2’39.2’’ ± 5.9’’ ±6’’ − position of TeV signal incompatible with radio maximum SgrA East (7  ) van Eldik et al., ICRC (2007)

9. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier HESS J1745-290 energy spectrum − compatible with a power-law, cut-off energy > 6 TeV (95%CL) − spectral index:  = 2.29 ± 0.05 − integrated flux (>1 TeV)  = 1.87 ±0.1 10 -12 cm -2 s -1 − no apparent spectral variability (2003  2005)

10. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Non-variability of the HESS J1745-290 signal No periodicities/flares (a few minutes  1 year) 30th July 2005 No correlation with X-rays (Chandra) J.Hinton, M.Vivier et al, (HESS) ICRC 2007M.Vivier et al. (HESS) ICRC 2007

11. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Galactic Centre: spectral constraints 14 TeV 5 TeV 10 TeV − KK, bb and  +  - spectra with PYTHIA 3.625 − poor fit at the low energy end  incompatible with a DM only source − F.Aharonian et al., Phys.Rev. Letters, 97, 221102 (2006)

12. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Galactic Centre: exclusion plots MSSM predictions MSSM+WMAP MSSM limits excluded (95% CL) KK predictions KK limits (p)MSSM predictions: DarkSusy 4.1 MSSM limits: ≤ (1-10) 10 -24 cm 3.s -1 KK limits: ≤ 10- 24 cm 3.s -1

13. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Satellite galaxies of the Milky Way

14. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier The Sagittarius dwarf galaxy M54 -discovered in 1994 -distance: 24 kpc -behind the GC -core centered on M54 Majewski et al., (2003)

15. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier The Sagittarius dwarf galaxy -Spheroidal galaxy with a nucleus -Coincidence in position with the globular cluster M54 -Tidally distorted -Distance: 24 kpc King model fit "cusp" (Monaco et al 2004) - The luminous profile has 2 components 1) diffuse component well fitted by a King model: r c = 1.6 kpc 2) compact component well fitted by a compact core: r c = 1.5 pc Point-like signal (core region much smaller than the H.E.S.S. PSF).

16. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Sagittarius dwarf: data analysis -Target position corresponding to the globular cluster M54: RA = 18h54m40s DEC = -30d27m05s (J2000) -11 hrs of live time after data selection (2006) -Mean zenith observation angle: 19° No significant excess at the target position (blue triangle). Signal region: 0.14° circular region centered on the target position

17. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Limits on the  -ray flux and sensitivity The 95% C.L. limits on N  provides a 95% C.L. upper limit on the velocity weighted cross- section, depending on the DM halo profile: Dark matter profile NFW (with the Draco dwarf galaxy parameter, Evans et al. (2004)) Core profile (parameters fitted on observationnal data) Upper limit at the 95% C.L. on the number of  -rays at the target position (Feldmann & Cousins method):

18. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Constraints on WIMPs models pMSSMKaluza-Klein The core profile excludes KK models compatible with the DM relic density as measured by WMAP Some pMSSM models excluded in the case of the cored profile. ~ 2. 10 -25 cm 3 s -1 (core) ~ 6. 10 -24 cm 3 s -1 (NFW) ~ 5. 10 -26 cm 3 s -1 (core) ~ 10 -24 cm 3 s -1 (NFW)

19. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Conclusions and perspectives -Galactic Centre: strong signal with no-variable emission. Probably not of a DM origin. Signal from Sgr A East excluded. -Sagittarius dwarf: no signal, strong constraints for a cored profile. - pMSSM: ~ 2. 10 -25 cm 3 s -1 - KK: ~ 5. 10 -26 cm 3 s -1 -Many more results are coming soon (Canis Major, Sculptor, Carina). H.E.S.S. 2 is coming very soon ! (2009) - 5th telescope with larger dimensions: 28m in diameter - Lower energy threshold ~ 20 GeV : access to a larger part of WIMPs models

20. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier

21. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier The GC ridge diffuse emission SNR G.09 GC Before subtraction of the G.09 and GC sources. After subtraction of the G.09 and GC sources. The diffuse emission region correlates well to CS giant molecular clouds.

22. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Non-variability of the HESS J1745-290 signal -no peridiodicities in the H.E.S.S. signal (Lomb-Scargle periodogram & Rayleigh test) from a few minutes to one year. M.Vivier et al. (HESS) ICRC 2007

23. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier The radio-galaxy M87 in the Virgo cluster VLA 90 cm extension source TeV (99.9% CL) 3’ ≈ 13.7 kpc − Active Galaxy Nucleus (AGN) with a SMBH of (3.2± 0.9)10 9 M solar − distance = 16.3 Mpc − jet axis not aligned with the line of sight (20-40 deg, not a blazar) − TeV emission first detected by HEGRA (2003) − HESS related paper: Aharonian et al., Science, 314 (2006), 1424

24. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier The M87 TeV signal as seen by H.E.S.S. -13  detection in 89h (2003-2006) - point-like < 3’ (99% C.L.) - Power law energy spectrum:  = 2.22 ± 0.15 (2005)  = 2.62 ± 0.35 (2004) -Time variability in the measured flux: on year timescale (3.2  ) on day timescale (4  ) The time variability of the H.E.S.S. signal discards a sole DM origin and favors the central black hole as the production site of the TeV photons.

25. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Dark Matter annihilations fluxes predictions for M87 HESS Point Spread Fonction Radial mass profile of M87 « Romanowski, Kochanek (2001) » − « Fornengo et al (2004) » : HEGRA (MSSM)  profil halo Moore,  M  =1 TeV,  WW  (E>730 GeV) ~ 10 -16 /cm 2 /s − HESS predictions:  energy threshold ~ 400 GeV  Halo model from « Romanowski & Kochanek (2001) »  NFW profile fitted on observationnal data  M(r) is well-constrained  prédiction flux  (E>100 GeV) ~ 10 -15 /cm 2 /s ~1/1000 HESS sensitivity

26. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Modelling the Sagittarius DM profile Use the Jeans equation: -observable:  luminous density, velocity dispersion -Unknowns: M luminous+dark mass  anisotropy Assume  -solve for M(r) to get  dark or -fit dark matter halo parameter to reproduce 2 DM halo considered: -NFW (parameter fitted to ) -cored profile (with assumed to be flat, and analytic resolution of the Jean equation)

27. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Systematic uncertainties on the core modelling  max  = 0.14° S 0 = 24 kpc Core radius dependency

28. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Systematic uncertainties on the core modelling Our modelling Baryon fraction dependency Factor 2 if the baryon fraction in 100%

29. Rencontres de Moriond – Cosmology session – 2008 H.E.S.S. collaboration Matthieu Vivier Systematic uncertainties on the core modelling 50% effect on the value of Jbar Is the velocity dispersion profile asymptotically flat in the outer part of the halo?