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Ullrich Schwanke Humboldt University, Berlin, f or the H.E.S.S. Collaboration

Observations of Shell-type Supernova Remnants with H.E.S.S. Ullrich Schwanke Humboldt University, Berlin, f or the H.E.S.S. Collaboration. Overview. Introduction: supernova remnants (SNR) as possible cosmic ray sources What we now from X-rays H.E.S.S. results and interpretation

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Ullrich Schwanke Humboldt University, Berlin, f or the H.E.S.S. Collaboration

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  1. Observations of Shell-type Supernova Remnants with H.E.S.S. Ullrich Schwanke Humboldt University, Berlin, for the H.E.S.S. Collaboration

  2. Overview • Introduction: supernova remnants (SNR) as possible cosmic ray sources • What we now from X-rays • H.E.S.S. results and interpretation • RX J1713.7-3946 (“RX J1713”) - details • RX J0852.0-4622 (“Vela Junior”) – detailed 2nd paper soon to come • Summary and outlook

  3. Are SNRs the sources of cosmic rays ? • SNRs as accelerators for hadronic cosmic rays • Diffuse shock acceleration predicts power law spectrum E-2.0..2.2 • Conversion efficiency of O(10%) • Exploring SNRs using secondary x-rays and gamma-rays

  4. energy flux radio x-ray TeV energy Are SNRs the sources of cosmic rays ? • SNRs as accelerators for hadronic cosmic rays • Diffuse shock acceleration predicts power law spectrum E-2.0..2.2 • Conversion efficiency of O(10%) • Exploring SNRs using secondary x-rays and gamma-rays

  5. energy flux  radio x-ray TeV energy Are SNRs the sources of cosmic rays ? • SNRs as accelerators for hadronic cosmic rays • Diffuse shock acceleration predicts power law spectrum E-2.0..2.2 • Conversion efficiency of O(10%) • Exploring SNRs using secondary x-rays and gamma-rays electron accelerator synchrotron emission inverse Compton e

  6. hadron accelerator  0 production  0 Are SNRs the sources of cosmic rays ? • SNRs as accelerators for hadronic cosmic rays • Diffuse shock acceleration predicts power law spectrum E-2.0..2.2 • Conversion efficiency of O(10%) • Exploring SNRs using secondary x-rays and gamma-rays energy flux synchrotron emission e p radio x-ray TeV energy

  7. X-Ray Observations 2-10 keV SN 1006 (CHANDRA) Bamba et al. (2003) 0.4-0.8 keV

  8. X-Ray Observations 2-10 keV SN 1006 (CHANDRA) Bamba et al. (2003) 0.4-0.8 keV

  9. X-Ray Observations • Electrons leaving acceleration region move downstream by advection and diffusion • Synchrotron losses • Downstream size of filaments  upper limit on synchrotron loss time and lower limit on B field upstream downstream shock E. Parizot et al. (2006)

  10. H.E.S.S. TeV Observations RX J1713.7-3946 RX J0852.0-4622 Largest known TeV source 2o 0.75o

  11. H.E.S.S. TeV Observations RX J1713.7-3946 RX J0852.0-4622 Largest known TeV source 2o 0.75o

  12. RX J1713 H.E.S.S. 2004 ROSAT 1996 • Discovery in ROSAT All-Sky Survey • Mostly non-thermal X-rays • D ~ 1 kpc • CANGAROO observed TeV excess from western rim • H.E.S.S. 4-telescope obervations (33 h live-time) • Zenith angle 15-60° • Shell resolved!

  13. Correlation with X-rays • Correlation coefficient between TeV -rays (HESS) and X-rays (ASCA) is ~80% • Shocks  -rays

  14. RX J1713: Spectrum • 2003 and 2004 spectra compatible • Photon index 2.260.020.15 • Flux ~ 1 Crab • Spectrum extends up to 40 TeV  acceleration of particles up to ~100 TeV • Deviation from pure power-law at high energies

  15. Spatially Resolved Energy Spectra TeV photon index X-ray photon index H.E.S.S. 1.8 2.0 2.2 2.4 2.6 G. Cassam-Chenaï A&A 427, 199 (2004) TeV=const. difficult to understand in electron scenario

  16. Electron Scenario (1/2) energy flux energy flux SY IC SY IC E E • High B field, low electron injection  low IC level • Low B field, high electron injection  high IC level

  17. Electron Scenario (2/2) =2.2 at injection level =2.4 at injection level B=6 G B=8 G B=10 G • Simple one-zone model • Electrons and protons injected with same spectral shape; energy losses and particle escape out of the shell were considered • Need a B field of ~8 G to match flux ratio Simple electronic models do not work too well

  18. Hadron (+Electron) Scenario • Injection spectrum: power-law (=1.98) with exponential cutoff (at 120 TeV) • Injected energy 1051 erg, electron-to-proton ratio 5  10-4 • B field ~35 G, H density 1.5 cm-3

  19. Summary & Outlook • Two shell-type SNRs established as TeV -ray sources • Both sources were resolved; TeV morphology very similar to X-ray morphology • First ever spatially resolved TeV energy spectra (for RX J1713) • Observed flux is ~1 Crab, photon index ~2.2 • Question of electron or hadron acceleration remains difficult to answer (for the few objects we have) • H.E.S.S. II and GLAST will determine energy spectra in GeV domain

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