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VHE Gamma Ray Astronomy: a UK strategy for the next decade

VHE Gamma Ray Astronomy: a UK strategy for the next decade. Paula Chadwick for the University of Durham Johannes Knapp for the University of Leeds Richard Holdaway & John Womersley for RAL. Definitions & detection The international context Some recent highlights The UK situation

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VHE Gamma Ray Astronomy: a UK strategy for the next decade

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  1. VHE Gamma Ray Astronomy: a UK strategy for the next decade Paula Chadwick for the University of Durham Johannes Knapp for the University of Leeds Richard Holdaway & John Womersley for RAL • Definitions & detection • The international context • Some recent highlights • The UK situation • Our proposed strategy

  2. Generally E > 100 GeV at present VHE gamma rays can be defined as those detectable from the ground using the: Imaging Atmospheric Cherenkov Technique • (Multiple) Images of showers • Gamma rays form consistent pattern • Excellent gamma-hadron separation (~100%) • Showers located to ~0.1° at threshold • Point source location to ~ 20”

  3. Current Major IACTs

  4. Science topics Pulsars and PWN SNRs AGNs Dunkle Materie Space-time & relativity GRBs Dark matter Origin of cosmic rays Cosmology

  5. Integrated Pulse VERITAS-4 Four 12m diameter telescopes Davies-Cotton design, 345 mirrors FoV 3.5° 499 PMTs, pixel spacing 0.15° Two telescopes operating in stereo mode Four telescope array by end 2006 • USA: Smithsonian Astrophysical Observatory; Iowa State University;University of California, Los Angeles; University of Chicago; University of Utah; Washington University, Saint Louis • UK: Leeds University • Canada: McGill University • Ireland: National University of Ireland

  6. First Stereo Observations Markarian 421 at ~ 2 Crab in Jan/Feb 2006

  7. High Energy Stereoscopic System – H.E.S.S. Four 13m diameter telescopes Davies-Cotton design, 382 0.6 m diameter mirrors FoV 5° 960-pixel cameras Routine operations since January 2004 Germany: M-PIK Heidelberg; Humboldt University, Berlin; University of Hamburg; Ruhr University, Bochum; Landessternwarte Heidelberg France: LLR Ecole Polytechnique, LPNHE, PCC College de France, University of Grenoble, CERS Toulouse, CEA Saclay, Observatoire de Paris-Meudon, University of Montpellier II UK: Durham University Ireland: Dublin Institute for Advanced Studies Czech Republic: Charles University, Prague Armenia: Yerevan Physics Institute Namibia: University of Namibia South Africa: North-Western University

  8. Progress in VHE Gamma Rays… X 7 X 2 X 12 X 11 X 40

  9. RXJ1713.7-3946 2 telescopes with/without array trigger E > 800 GeV; angular res. 3 arcmin. 18.1 hours livetime, 20 Image from 2004 with all four H.E.S.S. Phase telescopes; 2 arcmin resolution, 33 hours livetime. Enomoto, R. et al.,Nature, 416, 823-826 (2002) Aharonian et al., Nature, 75, 432 (2004)

  10. Vela region Vela (Rosat) Vela Junior d ≈200 pc age ≈700 y

  11. Galactic Centre H.E.S.S. observations show a source which is consistent with the position of Sgr A* and with a nearby SNR. Significance with 2004 data > 30 Aharonian et al., Astron. Astrophys., 425, L13 (2004)

  12. 20 TeV Neutralino 20 TeV KK particle Dark matter annihilation? Preliminary proposed based on early H.E.S.S. data proposed before H.E.S.S. data Bergström et al, Phys. Rev. Lett., 94, id. 131301 (2005)

  13. Diffuse Emission

  14. Galactic Plane Scan

  15. Source spectrum G = 1.5 EBL AGN Spectra &ExtragalacticBackgroundLight 1ES 1101-232 Z = 0.186 H2356-309 (x 0.1) Z = 0.165 Preliminary

  16. AGN Spectra &ExtragalacticBackgroundLight Source spectrum  Upper limit on EBL too much EBL 1 ES 1101 G = 2.9±0.2 H 2356 (x 0.1) G = 3.1±0.2 Preliminary

  17. Spectra &ExtragalacticBackgroundLight UV EBL Not really a solution: add huge amount of UV photons to EBL  problems with source energetics, X-ray/gamma-ray SED ratio too much EBL 1 ES 1101 G = 2.9±0.2 H 2356 (x 0.1) G = 3.1±0.2 Preliminary

  18. Reference shape HESS limits Spectra &ExtragalacticBackgroundLight • EBL resolved • Universe more • transparent X measure- ments upper limits X lower limits from galaxy counts

  19. Cosmic Background – hidden quasars MWB IRB X XRB Stars/AGN Cosmic AGN

  20. The UK VHE Gamma Ray Scene • A long UK history in VHE gamma ray astronomy • Two UK groups – Leeds (VERITAS) and Durham (H.E.S.S.) • Both provide a strong contribution to their respective collaborations based on over 20 years’ experience • UK thus has access to data from both North and South, but our efforts are divided • Joint UK strategy defined

  21. Our Strategy • Start a UK Gamma Ray Association to co-ordinate activities e.g. multi-instrument campaigns, development • Exploit VERITAS – similar performance to H.E.S.S. but different, Northern sky targets – total cost ~ £100k - £200k p.a. Minimal capital investment. • Jim Hinton at Leeds to become involved in H.E.S.S. • Sizeable (~ £1M) capital contribution to H.E.S.S. II aiming at higher sensitivity at low energies. • RAL joins VHE gamma ray effort, other groups also interested (e.g. Liverpool, Oxford). • H.E.S.S. & H.E.S.S. II to be the experiment towards which UK gamma ray activities gravitate. • Post-2010 – plan UK contribution to the next major VHE gamma-ray facility (ESFRI?). Development work to start now.

  22. H.E.S.S. II A single, 28m diameter dish Lowers threshold to ~ 20 GeV in standalone mode Improves overall array sensitivity in coincidence Key science questions: AGN population & the EBL; microquasar & XRB models; hadrons vs. leptons in SNR; pulsar detection; EGRET UiD sources; gamma ray bursts; dark matter.

  23. After H.E.S.S. II? GLAST Crab 10% Crab MAGIC 20 wide-angle 10 m telescopes de la Calle Perez, Biller, astro-ph 0602284 30 m stereo telescopes Konopelko Astropart.Phys. 24 (2005) 191 H.E.S.S. Current Simulations 1% Crab

  24. In summary… Array development & design Array build H.E.S.S. II Build Exploitation of H.E.S.S. I & II Exploitation of VERITAS 2006 2007 2008 2009 2010 2011

  25. Why North and South? • Understanding both AGN & SNR requires population studies • Specific objects in both hemispheres require investigation (e.g. Cas A, Tycho, Galactic Centre, LMC/SMC…) • Full sky coverage is desirable for multiwavelength multi-target campaigns

  26. Technical Expertise of UK groups • CCLRC/RAL: large scale project management/delivery; instrumentation (esp. single photon detection, fast electronics, communications); detector assembly (design/validation, test assemblies); data analysis & physics (data management, ‘gridification’) • Durham University: mirror design/manufacture, atmospheric monitoring, calibration, simulations. • Leeds University: fast signal transmission; advanced trigger systems; photodetectors; simulations.

  27. The UK GRA • Start with a general discussion between all members of involved and interested groups • Form a small committee of (say) 2 members from each group • Quarterly meetings to enable updating • Regular reviews of strategy • Eventually a more formal orghanisation with MoU etc.

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