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World-wide collaboration ?

A personal view on the global future of TeV γ ray astronomy and Japan Tadashi Kifune world-wide collaboration and future of Japan/CANGAROO ? TeV gamma rays from nearby galaxies . World-wide collaboration ? . Better sensitivity by (1-2?) orders of magnitude

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World-wide collaboration ?

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  1. A personal view on the global future of TeVγ ray astronomy and JapanTadashi Kifune world-wide collaboration andfuture of Japan/CANGAROO ?TeV gamma rays from nearby galaxies

  2. World-wide collaboration ? • Better sensitivity by (1-2?) orders of magnitude requires worldwide efforts to be combined a larger number of IACTsto cover a larger area wider energy region to cover • the role of small group (like CANGAROO) ? • “Collaboration and competition” : Multiple independent efforts • Ground –based observation: north-south, …… “In the long-term, the collaboration shouldbe extended to coordinate the observationprogram taken with facilities located atdifferent latitudes or longitudes.” (AGIS document) World-wide efforts for several observatories: CTA, AGIS, …..

  3. What is going on …… in Japan • To join wider international collaboration. “Expression of interest” : in the CTA meeting at the beginning of this year…….. “MOU with AGIS” : to be discussed • Repairing work of CIII telescope several developing works of technology • Vision in the long term : scientific goal, concept, way of collaboration “The direction to be taken” not made clear yet, ……… generally in whole of the society, • Various reformations going on:rapid change, in dismay, ……. universities,“funding system”, “Academy of Japan Science”, …… ICRR: (neutrino, cosmic rays ------ CANGAROO, Tibet, TA gravitational wave) …..

  4. Aimof , and, lessonsfromCANGAROO--- from past to future ---- • The aim wasto uncovera wealth of Galactic sources in the southern sky limitation of apparatus / surrounding conditions the Woomera site nearly at the sea level • Plastic mirrors : chosen for its weight less than glass but not with very good PSF, reflectivity, • “extended emission ” of Galactic sources to see with the CANGAROO imaging Cherenkov telescope • To scan the Galactic disc : needwider FoV What sort of science is to be aimed in the next step ? Apparatus may not have been well matched with the Galactic sources aimed, Detection system in the next step ?

  5. Current status of ~70 sources ？ Flux in 10-12 cm-2 s-1 TeV-1 at 1TeV

  6. The break-through of imaging Air Cerenkov Telescope Δθ≈ 1o0.1o 1st generation Area >~105m2 ΔΩ~1msr a number of telescopes Ω~1sr like GLAST? aperture~10mΦ to ~30mΦ (MAGIC and H.E,S.S.) stereo~4 telescopes 2nd generation

  7. Activities of White Paper Team • • Formation of six working groups: • -- Dark Matter, • - Compact Galactic Objects, • - Supernova Remnants and Cosmic Rays, • - Extragalactic (Non Gamma-Ray Bursts), • - Gamma Ray Bursts, • - Technical Working Group. • • Solicitationf of contributions from astroparticle physics community: • - Via email & special sessions on meetings (First GLAST Symposium, • Feb. 2007 (Palo Alto, CF), APS Meeting, April 2007 (Jacksonville, FL)). • • Writing of White Paper in 2006 & 2007: • - Executive summary (in progress). • - Detailed discussion (largely finished). • - Appendices (Glossary…, tbw). Quantum gravity …….. Structure formation Extragalactic diffuse Normal galaxy is no fun?

  8. To clarify/understand “the Origin/nature of CRs”; To explain cosmic ray spectra, To understand the knee, to know the cut off energy of acceleration, propagation and confinement in the Galactic disk to accumulate more number of SNRs, PWNe, XRBs….: to understand better. Any other route to take?

  9. Implication of EGRET results on LMC and SMC : CRs of our Galaxy are not of extragalactic origin From A.Woflendale (Durham) New insight fromcomparing the total emission from different galaxies verified excluded Galaxy LMC SMC

  10. EGRET observation on SMC,LMC and M31 LMC 2 x 10-7 cm-2s-1 > 100 MeV SMC < 5 x 10-8 cm-2s-1 > 100 MeV M31 <1.8 x 10-8 cm-2s-1 > 100 MeV • LTeV ～ Legret ∙(100MeV/1TeV)(α-1) = Legret∙10-4(α-1) α=2.2~2.6: power index of gamma ray spectrum ? • TeV flux extrapolated from the EGRET α= 2.2 ～ 2.6: < 2x10-13 ～ 2x10-15 cm-2s-1 for M31 2x10-12~2x10-14 cm-2s-1 for LMC

  11. Upper limits / flux from objects in nearby galaxies With Sensitivity of 10-14~10-13 cm-2s-1, Number of γ rays for>1TeV with 10km2 detection area SN1987Ain LMC <5x10-13cm-2s-1(5TeV) <1037erg s-1 0.05Mpc CANGAROO Whole of M31 <2x10-11cm-2s-1 <2x1039erg s-1 0.8Mpc VERITAS objects in M31 <3x10-12cm-2s-1 <3x1038erg s-1 0.8Mpc HEGRA M87 ~ 10-13cm-2s-1 3x1040erg s-1 16Mpc HESS Perseus cluster <(3-8)x10-12cm-2s-1 <(2-4)x1042erg s-1 75Mpc VERITAS ……………………………. ………. ……. (10-14~10-13 cm-2s-1)x 10 km2 x 105 s (1days, ~10nights obs) ≈ 102 ~ 103 gamma rays

  12. Emission from a galaxy similar to the Milky Way Galaxy • Emissivity q(photon Hatom-1 s-1 sr-1), size of Galaxy : a~10kpc : Fin= qa : viewed from inside • galaxy at distance D Fout= qa3 D-2 : from outside • Fout = (a/D)2・Fin~ 10-4(D /1Mpc)-2・ Fin

  13. FIGURE 3.Energy BACK TO ARTICLE -ray flux per unit 2 x 10-8 cm-2s-1sr-1 for > 1TeV 2 x 10-9 cm-2s-1sr-1 for > 10TeV

  14. Emission from a normal galaxy similar to the Milky Way Galaxy EGRET:(1~3)x10-4cm-2s-1sr-1 (>100MeV) ΔΩ= 0.1→ ~10-5 cm-2s-1 α= 2.2~2.6 →2x10-10 ~10-12 cm-2s-1(>1TeV) x 10-4 → 2x(10-14 ~10-16) cm-2s-1(>1TeV, 1Mpc) Diffuse emission HESS : 2x10-8cm-2s-1sr-1 (>1TeV)and Milagro ΔΩ= 0.1 ~ 0.01→ 10-9 ~10-10 cm-2s-1 (>1TeV) x 10-4 → 2x(10-13 ~10-14) cm-2s-1(>1TeV, 1Mpc) Summation of all Galactic sources 2.3 x 10-10 cm-2s-1( at 1TeV) x (10-4 ~10-5) → 2x(10-14 ~10-15) cm-2s-1(>1TeV, 1Mpc)

  15. >1TeV γ rays from nearby galaxies • LMC 10-12~10-14 cm-2s-1extrapolated from EGRET • “normal galaxies” (similar to Milky Way Galaxy) flux estimated from EGRET and HESS data: 10-13 ~10-16 cm-2s-1at D = 1Mpc 10-14 ~10-17 cm-2s-1at D = 3Mpc • more gamma rays from more massive galaxies • Milky Way Galaxy :1.4 x 1011Msun, LMC :1.0 x 1010Msun, SMC :1.7 x 109Msun • M31 (Andromeda) galaxy : 7 x 1011Msun • SN explosion rate , • Confinement time, ……….. • Starburst galaxy, active galactic nuclei of jet axis off line of sight, …. galaxy nuclei having massive black holes 10-13~ 10-12 s-1cm-2 ? • M87 : D=16Mpc, time variable TeV gamma ray? 109 solar mass BH HESS: LTeV = 3 x 1040 erg s-1, F = 10-12 erg cm-2 s-1 • Blazars

  16. current sourcesandflux from normal galaxies X 10-12 cm-2 s-1 TeV-1 at 1 TeV

  17. Possible CTA sensitivity From W.Hofmann GLAST Crab E.F(>E) [TeV/cm2s] 10% Crab MAGIC M31 AGN and pulsar physics H.E.S.S. Exploring the cutoff regime in Galactic sources Normal galaxies at ~3Mpc 1% Crab A deep look at the TeV sky

  18. Sensitivity of Synoptic TeV Telescopes Crab GLAST HESS/VERITAS Whipple Tibet Milagro ARGO HAWC TibetMD sHAWC (From G.Sinnis) M31 at ~3Mpc

  19. Scan of 5 degree x 5degree region is not an easy work However, ~30 SNRs and other interesting sources LMC is expected to have the highest flux of TeVγ rays among nearby galaxies To compare the morphology with what GLAST will soon provide at ~ 1GeV

  20. Expectedflux of aTeVγray in 0th approximation (by assuming Brightness ~ TeV flux) flux？) X 104 X 10

  21. TeV gamma rays from normal galaxieswill tell us about …… • Disc: matter, B, CR distribution • Σpoint sources SNR, PWN, ….. • nucleus of galaxy : BH,…… • Ratio of disc emission to Σpoint sources Emax acc. e/p, TSN, E - δ (confinement time in disk), …. • Morphology of intensity and spectrum cosmic rays: propagation/balance against galactic structure

  22. Propagation/confinement of CRs • E-α ;α≈ 2.7 = (2.0 ~ 2.2) + δB / C • D ≈ Eδ by assuming T ~ dCR2 / D • CR Anisotropy ≈λ/ dCR ~ D ~ Eδ: not as observed dCR : thickness of CRdistribution in Galactic disc • Dependence of TeVγ-ray emission on M? (M: total mass of galaxy)

  23. summary 1: the high energy structure of “galaxy”? • Milky way Galaxy in comparison with other nearby galaxies • L (Mgalaxy) ? L ~ M or M2 or …… • high energy non-thermal process of galaxies • Point sources / emission from disc ? e/p, anisotropy, reacceleration, …. • Radiation from massive black hole at the center of the galaxy? • Contribution from DM ? • CRs as high as 1020eV ?  10-100TeV

  24. summary2: perspective of “nearby galaxies”? • M31 in the north and LMC in the southto begin with. the flux of 10-15~10-13 cm-2s-1 is expected → 10 ~ 1000 γ ray photons with (10km2・1day) hopefully to detect galaxies of having active nucleus like M87 at <~10 Mpc • Galaxies at ~ 3Mpc : △θ ~ 1 degree morphology of a galaxy • galaxies at ~10 Mpc : detection area > 10km2 • several tens Mpc~ the distance of GZK cut off very Wide FoV : ~1 srFoV

  25. additional thoughts and a remark Some sayings (in Japan) : “Too many captains for a boat, the boat would go climbing up a mountain” “Chase for two rabbits, to lose the both” “ A hunter chases a deer, not seeing the mountain, not knowing where he is” “Nearby normal galaxy” is a unique object That will combine the TeV γ ray study of Galactic and extragalactic phenomena, and will deepen our understanding of the origin of cosmic rays.

  26. Intrinsic nature peculiar to Galactic / extragalactic sources or Detection bias ? • Galactic sources : extended/affected by disk emission serious background lights from bright area of the sky subtraction by “on/off mode” of observation • Extragalactic sources: time variable emission dark area of the sky more phenomena still left as to be observed

  27. Acceleration site • Emax acc. ? : > 10TeV, many objects Wefel :“naked SN” 5 x 1013 eV ; Ptuskin SN1a, ib, II “SNR in wind” 4 x 1015 Hypernova novae 2 x 1011 environmental conditions • What is TSN ? : morphology, propagation a time for SNR to merge into interstellar space Likely to vary from object to object independent of E ? Really, TSN =105 yrs ? What is interstellar space, bubble, …..? • Some “ideal” source ? • To scan all sources ?

  28. Scenic vista of ground-based γ-ray astronomy, on speculation 2005 2010 2015 Related events in other bands TeV γ-rays from GZK cut off? Galactic Disc? Absorption cutoff by Infrared radiation? PeV to EeV γ-rays Normal galaxies? GRB? DM, dark energy “cluster of galaxies” to extend γ-ray horizon? How many GLAST sources? “pair halo” Advanced IACTs to further study these phenomena Extragalactic diffuse emission?:

  29. Energy flow of 1020eV CRs • Flux of CRs >1020eV f = (0.5-5)x10-19cm-2s-1 (from all the sky) ≈ (one century ∙ 1km2)-1 = 10-19cm-2s-1 F=10 eV cm-2s-1 = 10-11 erg cm-2s-1 One 1020eV is equal to 108TeV photons, giving/corresponding to TeV flux of ~ 10-11 erg cm-2s-1 if coming from only one source • Number of sources F∙4πD2/L ~ 100 → 10-13 erg cm-2s-1 for D=100Mpc, L = 1040erg s-1

  30. several attractive directions GZK?? Number of telescopes, field of view, ... 1012 Auger Area S (m2) Horizon due to Absorption γ+ CMB photon → e+ + e- Towards better sensitivity, more sources Towards more energetic 108 IACT 109 photons We are here 104 103 photons 1 photons 106 sources 104 sources? Newton ~1 sources Glast 100 Chandra Suzaku keV MeV GeV TeV PeV EeV ZeV

  31. Gamma rays from massive BH in the center of galaxy ? • TeV Blazars Fx≈ Fγ~10-11~10-10 erg s-1 cm-2 • Nearby galaxies Compact x-ray sources in the center of 21 out of 39 nearby face-on and spiral galaxies with available ROSAT HRI data, as to have Lx (2-10keV) ~1038 ~1040 erg s-1 Fx (2-10keV)~10-13~ 10-11 erg s-1cm-2 from Colbert and Mushotzky, Ap J (1999) Fγ~10-13~ 10-11 erg s-1cm-2 ??

  32. Point Sources ? • Anisotropy, magnetic field, distance, …. • “Micro anisotropy”? 8 doublets and 2 triplets out of 92 events (> 4x 1019eV; AGASA, Fly’s Eye) 10-6 -10-5 Mpc-3 sources ; 1042-1043 erg s-1? • If no anisotropy → Top-down mechanism?

  33. Beyond the horizon?Propagation of gamma-rays(α=2.0) Hard spectrum In the region of 10~100 TeV Large extension of angular size Depending on B, distance, …… Distribution of photon number Energy

  34. Point Sources ? • Anisotropy, magnetic field, distance, …. • “Micro anisotropy”? 8 doublets and 2 triplets out of 92 events (> 4x 1019eV; AGASA, Fly’s Eye) 10-6 -10-5 Mpc-3 sources ; 1042-1043 erg s-1? • If no anisotropy → Top-down mechanism? TeV gamma ray To solve the argued topics of 1020eV CRs

  35. Estimate by numerical calculation • F(E) = 7.4 x 10-14 ∙ (LCR/1043 erg s-1)∙(d/10Mpc)-2 x (E/140TeV) -1/2 photons cm-2 s-1 ? for E < me2/εCMB ~ 140TeV ≈10-13 photons cm-2 s-1 for 10 TeV from Ferrigno, Blasi, De Marco, Astroparticle Phys 23, 211 (2005)

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