2. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 H.E.S.S. and (Ultra High Energy) Cosmic Rays Jim Hinton (MPI-K Heidelberg) for the H.E.S.S. Collaboration: MPI Kernphysik, Heidelberg Humboldt Univ. Berlin Ruhr-Univ. Bochum Univ. Hamburg Landessternwarte Heidelberg Univ. Kiel Ecole Polytechnique, Palaiseau College de France, Paris Univ. Paris VI-VII Univ. Montpellier II CEA Saclay CESR Toulouse LAOG Grenoble Paris Observatory Durham Univ. Dublin Inst. for Adv. Studies Charles Univ., Prague Yerewan Physics Inst. Univ. Potchefstroom Univ. of Namibia, Windhoek

3. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Outline VHE  -rays as tracers of cosmic-ray acceleration and propagation The H.E.S.S. experiment Results from H.E.S.S. The Galactic Centre The Supernova Remnant RX J1713

4. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004  -rays from cosmic rays It is hard to accelerate and propagate cosmic rays without producing  -rays Interactions of cosmic rays with nucleons, radiation fields and magnetic fields all lead to  -ray production often peaks in the GeV-TeV regime UHECR accelerators within the GZK volume could well be detectable by current TeV gamma-ray detectors

5. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Example: acceleration by supermassive black holes It has been suggested (Boldt, Levinson,...) that UHCR could be accelerated by compact dynamos at the cores of 'quaser remnants' or ex-AGN. Fast rotating supermassive black hole embedded in a magnetic field produces a huge emf – could accelerate protons to 10 20 eV Curvature radiation in the TeV regime is the dominant energy loss mechanism Should be bright TeV sources (Neronov et al 2004) The supermassive black hole in our galaxy could accelerate to around 10 18 eV (AGASA anisotropy?)

6. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004  -rays from UHECR propagation Interactions of UHECR with the CMBR lead to the expected GZK cut-off but also produce secondary particles: p +   p +  0, p +   p + e + + e - and hence to  -rays via  0   and Inverse Compton Scattering These  rays in turn interact with the universal radiation fields (CMBR, IR and Optical) and an electromagnetic cascade begins At energies << 10 TeV the universe becomes transparent to  -rays (out to z ~0.1) and the cascade ends For reasonable assumptions on source strength and on extragalactic magnetic fields, such cascades should be detectable by H.E.S.S. (Ferrigno, Blasi, De Marco 2004) One complication is that emission may not be point-like expect extended emission due to magnetic deflections in the cascade, and from diffusion of UHECR out of acceleration region  halos (~ 1 degree)

7. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004  -rays from UHECR propagation Predicted gamma-ray fluxes for a UHECR accelerator at 100 Mpc (Aharonian 2002): H.E.S.S. has a wide field of view and very good sensitivity around 1 TeV – ideal for these studies Auger clusters could be H.E.S.S. targets within 1 degree within 1 degree approx HESS Sensitivity 1 degree

8. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 High Energy Stereoscopic System In Namibia, 1800 m a.s.l. Telescopes 4x in 120 m square 15 m focal length 13 m diameter 107 m 2 reflectors Cameras 960 PMT pixels Each 0.16 o, 5 o FoV 16 ns integration gate 'light-in, light-out' 4 Telescope system completed December 2003

9. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Detection principle: Stereoscopic imaging of Cherenkov light from air-showers Large collection area Multiple views of the shower improved direction improved energy improved rejection of background (cosmic rays!)

10. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Specifications Energy range 100 GeV  10 TeV Energy resolution 15 - 20% Angular resolution 0.05 - 0.1 degrees Sensitivity 1% of the flux from the Crab Nebula in 25 hours

11. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Performance Trigger rate versus threshold agrees well with simulations Array is triggering on a two telescope coincidence Operating range is well outside region dominated by the night sky background light Operating threshold d NSB

12. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Crab Nebula Preliminary 3-Telescope data (2003) 54 , (27  /hr 0.5 ) 10.8 +/- 0.2  /minute @ 45 degree zenith angle

13. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Comparison with simulations Very good agreement between simulations and real  -rays: the excess  -ray events from the Crab Nebula (so we always optimise our cuts on simulated  -rays, not on data) Image Width Angular Resolution Image Length

14. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Crab Nebula Spectrum agrees well with previous measurements dN/dE  E -2.63+/-0.04 Flux > 1 TeV: 1.98 x 10 -7 m -2 s -1 PRELIMINARY

15. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Updated sensitivity Simulations agree well with observed data  -ray rate, trigger rate, image shapes can confidently predict time required to detect source at 20 o zenith with E -2.6 spectrum: 0.01 Crab in ~25 hours 0.05 Crab in ~1 hour 0.10 Crab in ~20 minute 1.00 Crab in ~30 seconds Threshold is 100 GeV at zenith, 120 GeV after cuts

16. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Official detections by H.E.S.S. so far… Crab Nebula (2003, 3 Tel.) - 54 sigma PKS 2155 (2003, 2 Tel.) - 45 sigma Mrk 421 (2004, 4 Tel.) - 71 sigma PSR B1259 (2004, 4 Tel.) - 8 sigma RX J1713 (2003, 2 Tel.) - 20 sigma Sagittarius A* (2003. 2 Tel.) - 11 sigma Very confident detections – all but Mrk 421 and PSR B1259 were confirmed independantly in datasets from two hardware configurations

17. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 The Galactic Centre  -rays detected by CANGAROO and Whipple but: Very complex region - lots of potential sources of  -rays Sagittarius A* - supermassive black hole - curvature radiation of accelerated protons? Several SNR, including Sag-A East, 'standard' CR acceleration? Dark matter annihilation? To resolve the ambiguity we need precise spectrum well determined position

18. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Sagittarius A* H.E.S.S. 2003 2 telescopes, 16 hours E thresh = 160 / 250 GeV (2 data sets) 11  significance  Good source localisation  Hard energy spectrum  -ray candidates (hard cuts)

19. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Sagittarius A* - Source Location Chandra GC survey NASA/UMass/D.Wang et al. CANGAROO (80%) Whipple (95%) H.E.S.S. Contours from Hooper et al. 2004

20. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Point-like emission from Sgr A* direction H.E.S.S. Chandra F. Banagoff et al. 95% 68%

21. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Sgr A East Chandra & Radio NASA/G.Garmire (PSU) F.Baganoff (MIT) Yusef-Zadeh (NWU)  Sgr-A East not ruled out H.E.S.S. limit on rms source size

22. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Sagittarius A* - Spectrum DM annihilation: ? Curvature radiation: ? SNR Shocks: ? Shocks in winds: ?

23. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Galactic Centre – Dark Matter Neutralino annihilation? Use DarkSusy Expect two lines and continuum Power law index - 2.2 - 2.4 Cut off at roughly m  / 3 We see no lines and no cut off exponential cut off is limited to < 4 TeV Which implies m  > 12 TeV

24. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Supernova Remnant RX J1713 CANGAROO claim proton acceleration in RX J1713 Nature 416, 823 (25 April 2002) Extended, unresolved source Soft energy spectrum dN/dE  E -2.84 00 IC

25. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 SNR-Molecular Cloud Interaction? Fukui et al 2003 NANTEN CO Map + ASCA X-rays X-ray hot spots correspond to dense regions in the north and west of the remnant cloud provides target for accelerated protons:    Yasunobu Uchiyama RA

26. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 RX J1713 - X-ray ASCA 1-3 keV Data from Yasunobu Uchiyama

27. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 RX J1713 - TeV  -ray Off source data On source data

28. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 RX J1713 H.E.S.S. smoothed gamma-candidate map after image size cuts (> 800 GeV) - no background subtraction or acceptance correction Only two telescopes 18 hours 20 sigma c.f. ASCA (1-3 keV) Flux = 70% of Crab

29. Jim Hinton, 3rd International Workshop on UHECRs, Leeds, July 2004 Conclusions 1) TeV  -rays are good tracers of UHECR acceleration and H.E.S.S is a good instrument for this search 2) One century of work on the cosmic ray mystery and now we are getting close...