Masaki Mori. Institute for Cosmic Ray Research, University of Tokyo

Transcription

1 Masaki Mori Institute for Cosmic Ray Research, University of Tokyo International Workshop on Advances in Cosmic Ray Science March 17-19, 2008, Waseda University, Shinjuku, Tokyo, Japan

2 > TeV gamma-rays ~1 m 2 ~ sr A ~10 4 m 2 ~10-2 sr 2

3 Cherenkov light from gamma-ray showers Lateral distribution & Timing distribution 3

4 Shower profile Focal plane image Gamma Proton Gamma Proton Regular Irregular Sharp Diffuse Differentiation of gamma-rays from charged cosmic rays (image orientation angle) 4

5 Angular resolution 0.25deg 0.1 deg Energy resolution 30% 15% Better S/N (no local muons) ~10km S.Funk,

6 Base Satellite Ground Ground Gamma-ray detection Direct (pair creation) Indirect (atmospheric Indirect (shower array) Cherenkov) Energy < 30 GeV >100 GeV >3 TeV ( 100 GeV) ( 50 GeV) ( 1 TeV) Pros High S/N Large area 24hr operation Large FOV Good Large FOV Cons Small area High cost Low S/N (CR bkgd.) (but imaging overcomes this!) Small FOV Low S/N (CR bkgd.) Moderate 6

7 Rene Ong, ICRC2005 OG2 rapporteur talk (updated) 2007 VERITAS 7

8 TeV skymap 8

9 TeV skymap 9

10 TeV skymap 10

11 TeV skymap 11

12 TeV skymap 12

13 Jim Hinton, rapporteur talk, ICRC 2007 Kifune plot (Pulsar Wind Nebulae) (Subernova remnants) (Active Galactic Nuclei) (Unidentified sources) 13

14 SNRS SNR PWN BIN GC RIDGE YSC UID HBL LBL RGL FSRQ Classified by M. Mori RGL FSRQ LBL SNRS SNRS SNR HBL SNR PWN BIN GC 10 PWN RIDGE 8 UID BIN YSC UID 6 4 HBL 2 LBL 0 YSC GC RGL RIDGE FSRQ * Borders for SNR/PWN/UnID are vague 14

15 Jim Hinton, rapporteur talk, ICRC

16 Jim Hinton, rapporteur talk, ICRC

17 Long considered to be primary source for Galactic cosmic rays Pros: Energetic enough (10% of SN explosion energy) Size of object is large enough (R >> r g ) Many SNRs are bright radio sources: at least electrons are accelerated! Cons: Magnetic fields too low to go beyond ev Additional problem: adiabatic losses Cas A by Chandra 18

18 F. Ahanorian et al., arxiv: /0702 Jim Hinton, rapporteur talk, ICRC 2007 CTA 37B CTA 37A Comparable to PSF (0.09 ) J. Albert et al., A&A 474, 934 (2007) Good kev-tev Correlation! T.Tanaka, PhD thesis,

19 p/e ratio problem A.Bamba TeV Proton Π 0 decay Flat spectrum above 100MeV Electron Synchrotron X-rays Inverse Compton gamma-rays 20

20 Hard power-law + cutoff (?): ~E -2 exp(-e/e max ) RX J Electron model Proton model Synchroton Pion decay Inverse Compton Aharonian et al Berezhko & Voelk 2007 RX J Synchroton Brems. Inverse Compton Pion decay NO definitive answer for accelerated particles! Enomoto et al

21 D. Ellison et al., ApJ 661 (2007) 879 Difficult in the GeV-TeV region if magnetic field is strong! 22

22 J. Vink, astro-ph/ Y. Uchiyama et al., Nature 449, 576 (2007) G RX J by Chandra G G G G Variation in ~1yr time scale Need > 1mG! (locally) Protons produce TeV gamma-rays!? Counter arguments: Y.Butt et al., arxiv:

23 IC443 W28 12 CO X-ray 20cm 90cm 12 CO X [MAGIC, Albert et al., ApJ 664, L87,2007] [H.E.S.S., Aharonian et al., A&A, in press] Evidence of proton acceleration? 24

24 W. Hofmann, TAUP 2007, Sendai, September 2007 Major group in Galactic TeV sources 18/71 by Hinton (2007ICRC) Associated with relatively young (<10 5 years) and large spin-down pulsars Extended O(10pc), displaced from pulsars Gamma-rays via inverse Compton by electrons? LS

25 S. Funk et al., ICRC 2007 Shrinks! 28

26 HESS J HESS J HESS J Djannati-Atai et al., ICRC2007 Hoppe et al., ICRC2007 HESS J HESS J HESS J ms PSR (ATel1392 Carrigan et al., ICRC2007 Komin et al., ICRC2007 Aharonian et al. ApJ 777 (2007) 30

27 S. Funk, paper 390, 30th ICRC (Merida),

28 LSI (VERITAS/MAGIC) P orb ~26.5day MAGIC LS 5039 (H.E.S.S.) P orb ~3.9day VERTAS J. Albert et al., Science 312, 1771 (2006) V.A. Acciari et al., arxiv: F. Aharonian et al., A&A 460 (2006)

29 J. Albert et al., ApJ 665, L51 (2007) Black hole binary: M BH ~21M, M ~30M Relativistic jet v>0.6c: microquasar MAGIC 40hr obs. 4.9 seen in one 79 min. time slice Estimated significance: 4.1 after correction for statistical trials 33

30 Jim Hinton, rapporteur talk, ICRC

31 Aharonian et al., A&A 467, 1075 (2007) Young open stellar cluster Dozen O-stars Two Wolf-Rayet stars (~80M each)! Extended gamma-ray emission covering (but offset from) Westerlund 2 by HESS Due to collective effects of stellar winds in the cluster? A new source class? Churchwell

32 Van Eldik et al., ICRC 2007 Energy spectrum is not consistent with dark matter annihilation signal! L. Bergström, CTA meeting, Jan

33 F. Aharonian et al., Nature 439, 695 (2006) Raw CS Simple diffusion D=1.3 kpc 2 Myr -1 After subtraction Spectrum is harder than CR spectrum! Diffusion model by Busching et al. ApJ 656, 841 (2007) 37

34 F. Aharonian et al., A&A 477, 353 (2008) HESS J Two types: 1) No compelling counterparts 2) Dark in other wavelengths F. Aharonian et al., A&A 442, 1 (2005) 38

35 Funk et al., arxiv: v1 Coincident sources 39

36 Jim Hinton, rapporteur talk, ICRC

37 FSRQ Target photon p-synch cascade -synch cascade BL Lac 0 cascade Synchrotron peak Inverse Compton peak cascade Electron model Fossati et al Proton model Muecke et al. APh 18,

38 H.E.S.S. arxiv: W. Hofmann, TAUP 2007 Suzaku correl. PKS z = July 28, 2006 Peak flux ~15 x Crab ~50 x average Luminosity ~10 12 x Crab Doubling times 67, 116, 173, 178 ±50 s R BH /c ~ s MAGIC preliminary M. Hayashida, ICRC 2007 Fast variation Acceleration site & mechanism 42

39 Observed spectrum is affected by integalactic absorption! TeV + IR e + + e - Mean free path for e + e - pair production Jim Hinton, rapporteur talk, ICRC 2007 Protheroe & Meyer, Phys.Lett. B493 (2000) 1 We cannot discriminate source spectrum and intergalactic absorption! 43

40 H.E.S.S.: Aharonian et al., Nature 440, 1018 (2006) X X X Assume not harder than E -1.5 X Some models can be rejected 44

41 Raue, ICRC 2007 Upper limits: fluctuation/direct measurements Lower limits: source counts 45

42 MAGIC: M. Teshima, ICRC

43 C. Dermer, GLAST LAT AGN Science Group meeting, March 4,

44 10 TeV AGN More AGNs as energy threshold goes lower! 48

45 H.E.S.S.: Domainko et al., ICRC2007 A496 A3667 Perseus Coma A4038 A2029 Whipple: Perkins et al., ApJ 644, 148 (2006) 49 CANGAROO-III: Kiuchi et al., ICRC2007

46 W. Hofmann / M. Teshima, SLAC Workshop, Nov H.E.S.S. II MAGIC II 28m 50

47 CTA (Cherenkov Telescope Array): EU++ AGIS (Advanced Gamma-ray Imaging System): USA++ CTA 51

48 N S -2/3 2 (North/South) 1000 TeV sources if mcrab! Data: H.E.S.S. catalog 52

49 High energy window of the Universe is now open! Additional 2-3 decades of the photon spectrum Wider variety of sources than expected Cosmic accelerators are ubiquitous! Much work left to understand their physics Also: cosmology, fundamental physics Hoping to detect other class of sources Pulsars Star-forming galaxies, mergers Dwarf galaxies and dark matter Ultraluminous IR galaxies Clusters of galaxies Gamma-ray bursts 53