1. 1 TeVγ 線天文学の現状と将来 森 正樹 東京大学宇宙線研究所 「高エネルギー宇宙物理学の現状と将来」 2000 年 9 月 29-30 日 大阪大学

2. 2 Cherenkov telescope Cherenkov light from gamma-ray showers Lateral distribution & Timing distribution Konopelko, TMACD-V, 1999

3. 3 Imaging Cherenkov technique γp

4. 4 Satellite vs Ground-based gamma-ray telescope BaseSatelliteGround Gamma-ray detection Direct (pair creation) Indirect (atmospheric Cherenkov) Energy< 30 GeV ( → 100 GeV) >300 GeV ( → 50 GeV) ProsHigh S/N Large FOV Large area Good ⊿ θ ConsSmall area High cost Low S/N (CR bkgd.) (but imaging overcomes this!) Small FOV

5. 5 Cherenkov telescopes in the world ( 終了 )

6. 6 TeV gamma-ray source catalog 分類天体名グループ備考 Grade A (>5σ, multiple) Crab PSR1706-44 Mrk421 Mrk501 多数 CANGAROO, Durham 多数 Plerion AGN (BL Lac) Grade B (>5σ) SN1006 Vela RXJ1713.7-3946 PKS2155-304 1ES1959+650 BL Lac CANGAROO Durham Utah7TA Crimea SNR Plerion SNR AGN (BL Lac) Grade C (strong but with some qualifications) Cas A Cen X-3 1ES2344+514 3C66A Geminga B1509-58 HEGRA CT Durham Whipple Crimea CANGAROO SNR X-ray binary AGN (BL Lac) AGN Pulsar Plerion T.C. Weekes, Heidelberg WS, 2000

7. 7 TeV gamma-ray sky

8. 8 GeV gamma-ray sky Third EGRET catalog E > 100 MeV

9. 9 Crab nebula Unpulsed spectrum Aharonian & Atoyan, astro-ph/9803091 / Heidelberg WS, 2000 synchrotron IC

10. 10 Crab pulsar spectrum: where is the cutoff? Musquere, 26 th ICRC, 1999

11. 11 Supernova remnant: SN1006 T. Naito

12. 12 SNR: SN1006 - interpretation Synch+IC Only IC? No pro- tons? Naito et al. Astron. Nach. 320, 1999

13. 13 Supernova remnant: Cas A Goret et al. 26 th ICRC OG2.2.18, 1999 ● HEGRA 2000

14. 14 Supernova remnant: RXJ1713 RXJ1713.7-3946 “ SN1006 Jr. ” Muraishi et al., A&Ap 354, 2000 Tomida, Ph.D., 1999 CANGAROO

15. 15 AGN: Mrk 421 Rapid variability: Faster at TeV? Maraschi et al. ApJL 526, 1999 (April 1998) Whipple BeppoSAX

16. 16 AGN: Mrk 421 spectrum Synchrotron + inverse Compton model Takahashi et al. astro-ph/0008505 One-zone SSC model δ=14, B=0.14G synchrotroninverse compton

17. 17 AGN: TeV gamma-ray absorption by IR background Protheroe et al. astro-ph/0005349 IR Background Mean free path for e + e - pair production

18. 18 AGN: Mrk 501 spectrum Protheroe et al. astro-ph/0005349 Aharonian et al. A&Ap 349, 1999 Crisis? ↓

19. 19 Next generation projects

20. 20 H.E.S.S. (High Energy Stereoscopic System) 23 o 16'18'' S 16 o 30'00'' E 1800 m a.s.l.

21. 21 H.E.S.S. telescope 16 (4 init.) telescopes (120m spacing) Davies-Cotton design, F/0.8 (f=15m), 108m 2 mirror area (382 x 60cm  ) Camera: 960 x 29mm (0.16°) PMTs, 5° FOV, 600kg Readout: 1GHz FADC Total 52 ton each

22. 22 VERITAS Mt. Hopkins, AZ (Montosa canyon or north site) (Very Energetic Radiation Imaging Telescope Array System) 23 o N 111 o W >2000 m a.s.l.

23. 23 VERITAS telescope 7 telescopes (80m spacing) Reflector: Davies-Cotton design, D=10m (78.6m 2 ), f=12m, 244x 60cm hexagonal mirrors (glass) Camera: 499x 1 ” PMTs (0.15 o spacing), 3.5 o FOV Readout: 500MHz FADC? (This is the present 10m telescope: new design not available!)

24. 24 MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov Telescope) La Palma, Canary Island 28.75 o N 17.89 o W 2200 m a.s.l.

25. 25 MAGIC telescope Reflector: parabolic, D=17m (234m 2 ), f=17m, 976x (50x50cm 2 ) Al mirrors Camera: [classical] 397x 1 ” PMTs (0.10 o )+ 126x 1.5 ” PMTs (0.20 o ), 3.5 o FOV, ~100kg [standard] HPDs (center) + PMTs First Light in Summer 2001 (June 21, 2001)

26. 26 CANGAROO-III Woomera, South Australia 31 o 06' S 136 o 47' E 160 m a.s.l.

27. 27 CANGAROO-III telescope 4 telescopes (100m spacing) Parabola reflector consisting of 114 mirrors of 80cmφ (57m 2 ), f=8m, F/0.8 Camera: 4  FOV, 427x 3/4 ” PMTs (0.16 , Hamamatsu R3478UV, TTS 0.36ns) Readout: q-ADC & TDC

28. 28 Sensitivity of Cherenkov telescopes VERITAS, ICRC1999 Major backgrounds: p: CR proton e: CR electron  : CR muon NSB: night sky background

29. 29 Expected sensitivity

30. 30 Monitoring the gamma-ray sky ⇒？⇒？ ⇒？⇒？ ⇒？⇒？

31. 31 Future trends Lowering energy threshold ( → 5 GeV) Larger light collector Higher altitude Increasing FOV ( → 1 sr) “All-sky” TeV gamma-ray monitor

32. 32 High altitude Cherenkov telescope High altitude → higher photon density → lower energy → high statistics/ overlapping to satellites

33. 33 Cherenkov light density at high altitude Aharonian et al. astro-ph/0006163 γp

34. 34 Sensitivity of 4×50m 2 telescope array at 5km a.s.l. (e.g. Atacama) Aharonian et al. astro-ph/0006163

35. 35 All-sky TeV gamma-ray monitor 5 mφ, 1 sr telescope, 1 TeV threshold ・ CR rate (>1 TeV): 8 ･ 10 -6 cm -2 s -1 × 3 ・ 10 8 cm 2 = 3 kHz ・ Muons (>1 GeV): 7 ・ 10 -3 cm -1 s -1 × 2 ・ 10 5 cm 2 = 1.4 kHz ・ High threshold to reduce N.S.B. ・ 0.1 o resolution camera (many channels…) ・ Stereo if necessary ・ Good monitor for GRBs Not far away from the present technology! Kifune and Takahashi, TMACD-IV, 1997

36. 36 All-sky monitor optics EUSO/OWL type large FOV optics EUSO proposal, 2000 ↑ □ movable camera? ↓

37. 37 Science to come Plerions (pulsar nebula) Inverse Compton? ← synchrotron origin? Pulsars Cutoff in pulse component? ← polar cap/outer gap SNRs π 0 contribution? ← cosmic ray origin AGNs Gamma-ray source: e ± or p? Intergalactic IR ← cosmology EGRET unIDs, Neutralinos, GRBs, QG, Diffuse gamma, …, and more?

38. 38 Gamma-rays and cosmic-rays T. Kifune, 2000