Supernova remnants dense gas and g ray emission
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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

Roger Chevalier

University of Virginia

Vela

M. Lorenzi


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


Radiative shock

Ha,…

Recombination (to HI)

(jump)

Compressed region:

Thermal gas

Relativistic particles

Magnetic field

Draine & McKee 1993


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)


Drew + 2005

S147 Ha


Radio 11 cm Optical Ha Xiao et al. 2008


S147

Optical (Ha)

Fermi – LAT

Katsuta + 2012


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


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


PSR J0538+2817 now

40,000 years old

60,000 years old

Ng et al. 2007


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


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)


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


Radiative shock

emission

21 cm continuum emission

Lee et al. 2008


  • 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


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


IC 443 g-ray emission

Molecular clumps

EGRET

Fermi - GeV

VERITAS - TeV

MAGIC

Abdo + 2010


IC 443 – AGILE

Tavani et al. 2010


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)


Early interaction with dense mass loss

Shocked region:

X-ray and

radio emission,

expect g-rays


Optical light curves

powered by cs interaction

1044 erg/s

Stoll

et al.

2011


  • 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


SN 2006gy

Relativistic p cooling

SN 2010jl

D*=1 0.1 M/yr at 100 km/s

RAC + Irwin 2012


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


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


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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