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Supernova Remnants: dense gas and g -ray emission

Supernova Remnants: dense gas and g -ray emission. Roger Chevalier University of Virginia. Vela. M. Lorenzi. Evolution stages (Spitzer 1968, Woltjer 1972,…). 0509-67.5 in LMC. S147.

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Supernova Remnants: dense gas and g -ray emission

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  1. Supernova Remnants:dense gas and g-ray emission Roger Chevalier University of Virginia Vela M. Lorenzi

  2. Evolution stages(Spitzer 1968, Woltjer 1972,…) 0509-67.5 in LMC S147 Complications: mass loss from progenitor, complex interstellar medium, hydrodynamic instabilities, ejecta knots, effects of magnetic fields and relativistic particles • Ejecta- dominated • ~103 years • Nonradiative Sedov blast wave • ~104 years • Radiative shell • ~105 years • Return to interstellar medium

  3. Radiative shock Ha,… Recombination (to HI) (jump) Compressed region: Thermal gas Relativistic particles Magnetic field Draine & McKee 1993

  4. IC 443 D. Churchill Radio (Lee+ 2008) Optical Ha Duin & van der Laan (1975) showed detailed correspondence and developed model of radio from compressed IS fields and particles Application to g-ray emission: Chevalier (1977), Blandford & Cowie (1982)

  5. Drew + 2005 S147 Ha

  6. Radio 11 cm Optical Ha Xiao et al. 2008

  7. S147 Optical (Ha) Fermi – LAT Katsuta + 2012

  8. Models for S147 • Non-radiative blast wave, radiative filaments (Katsuta +) • Distance – 1.3 kpc • Age – 30,000 yr • E=(1-3)×1051 erg • n0=2-6 cm-3 (fil.) • vsh ~ 100 km/s • f=0.001-0.008 (filling factor of filaments) • Blast wave: n0=0.03-0.1 cm-3, vb=500 km/s

  9. S147 in radiative phase? • Pro • Morphology • Diffuse optical emission is radiative shock emission • Filaments have comparable velocities to diffuse emission (Kirshner, Arnold 1979); filaments – edge on shocks plus intersecting shock regions • Non-detection of X-rays (Sauvageot + 1990) • Con • Need age ≥ 60,000 yr • Distance ~0.8 kpc

  10. PSR J0538+2817 now 40,000 years old 60,000 years old Ng et al. 2007

  11. Models for S147 • Non-radiative blast wave, radiative filaments (Katsuta +) • Distance – 1.3 kpc • Age – 30,000 yr • E=(1-3)×1051 erg • n0=2-6 cm-3 (fil.) • vsh ~ 100 km/s • f=0.001-0.008 (filling factor of filaments) • Blast wave: n0=0.03-0.1 cm-3, vb=500 km/s • Radiative shell … • 0.8 kpc • 60,000 yr • ~1×1051 erg • 1-2 cm-3 • ~ 100 km/s • f~1

  12. S147 g-ray emission Escape from dense shell? Fermi ~1×1034 erg/s (Katsuta + 2012) With standard assumptions (shock acceleration of IS cosmic rays, compression to cool shell), radiative shell model overpredicts luminosity by ≥10 (Tang & RAC)

  13. IC 443 – a molecular cloud interactor Pulsar All molecular emission Radio continuum Shocked CO contours Lee et al. 2012 21 cm continuum emission Lee et al. 2008

  14. Radiative shock emission 21 cm continuum emission Lee et al. 2008

  15. Column density of HI is about as expected for radiative shell in 10 cm-3 gas Shocked HI contours on optical image Lee et al. 2008

  16. Radiative shell/clump interaction model (Chevalier 1999) Applied to IC 443, W44, 3C 391 Competing model: nonradiative blast wave in intercloud region (Reach + 2005, Uchiyama + 2010) High pressure

  17. IC 443 g-ray emission Molecular clumps EGRET Fermi - GeV VERITAS - TeV MAGIC Abdo + 2010

  18. IC 443 – AGILE Tavani et al. 2010

  19. IC 443 • Observe ~1035 ergs/s in g-rays, which is close to prediction in radiative shell model • But, unlike radio, g-rays are primarily from region of molecular interaction • J (jump) and C (continuous) shocks are present • Possible shell interaction with clumps • Crucial aspect may be mass • g-rays from radiative shell are expected (as in S147)

  20. Early interaction with dense mass loss Shocked region: X-ray and radio emission, expect g-rays

  21. Optical light curves powered by cs interaction 1044 erg/s Stoll et al. 2011

  22. SN 2006gy faint in X-rays near maximum light, ≤1040 erg/s. Reasons: • Inverse Compton cooling by photospheric photons more important than bremsstrahlung • Comptonization in the cool wind reduces energy of the highest energy X-ray photons • Photoelectric absorption in the cool wind

  23. SN 2006gy Relativistic p cooling SN 2010jl D*=1 0.1 M/yr at 100 km/s RAC + Irwin 2012

  24. SN 2010jl X-ray Chandra Dec 2010, t ~ 2 months T>12 keV NH ~ 1e24 cm-2 L~1042 ergs/s Chandra Oct 2011, t ~ 1 year T>8 keV NH ~ 3e23 cm-2 L~1042 ergs/s P. Chandra, RAC,…. 2012

  25. Fermi Model A – like SN 2006gy Emission Allowing for pair production in matter and g-g pair production Model B – like SN 2010jl Assumes d= 10 Mpc CTA from Murase + 2011 also Katz + 2011

  26. Final remarks Interpretation of g-ray emission can depend on model for the remnant (S147) Interaction with molecular clouds is complex and multiple emission components are likely Detecting a very young SNR will take fortunate nearby event with strong interaction

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