I. Grenier Pulsar wind nebulae Isabelle A. Grenier Université Paris 7 & CEA Saclay I. Grenier useful bibliography Gaensler & Slane, astro-ph/0601081 (with many references to observations) Arons J. 2004, Adv. in Space Research 33, 466 Rees & Gunn 1974, MNRAS 167, 1 Kennel & Coroniti 1984, ApJ 283, 694 and ApJ 283, 710 Chevalier, R. 1982, ApJ 258, 790 Romanova, Chulsky & Lovelace 2005, ApJ 630, 1020 Wilkin 1996, ApJ 459, L31 Bucciantini et al. 2003, A&A 405, 617 Blondin, Chevalier, Frierson 2001, ApJ 563, 806 van der Swaluw et al. 2003, A&A 397, 913 de Jager et al. 1996, ApJ 457, 253 Aharonian et al. for HESS, 2005, A&A 448, L43 and A&A 432, L25 and A&A 435, L17 and A&A 442, L25
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I. Grenier
Pulsar wind nebulaePulsar wind nebulae
Isabelle A. GrenierUniversité Paris 7 & CEA Saclay
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useful bibliographyuseful bibliography
Gaensler & Slane, astro-ph/0601081 (with many references to observations)Arons J. 2004, Adv. in Space Research 33, 466Rees & Gunn 1974, MNRAS 167, 1Kennel & Coroniti 1984, ApJ 283, 694 and ApJ 283, 710Chevalier, R. 1982, ApJ 258, 790Romanova, Chulsky & Lovelace 2005, ApJ 630, 1020Wilkin 1996, ApJ 459, L31Bucciantini et al. 2003, A&A 405, 617Blondin, Chevalier, Frierson 2001, ApJ 563, 806van der Swaluw et al. 2003, A&A 397, 913de Jager et al. 1996, ApJ 457, 253Aharonian et al. for HESS, 2005, A&A 448, L43 and A&A 432, L25 and A&A 435, L17 and A&A 442, L25
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synchrotron nebula in a supernova remnantsynchrotron nebula in a supernova remnant
SNR G292.0+1.8 + PSR J1124-5916P = 135 ms, age = 1.7 kyr
PSR 1957+20 « Black Widow »recycled ms pulsarsupersonic motion in the ISMbow shock confines the windnebulaD ~ 1.5 kpc
40 to 50 PWN knownin the Milky Way + LMC + SMC
from most energetic youngpulsars (bias)
4 1029 W ≤ Ėpsr ≤ 5 1031 W“round” PWNe for young pulsars
τpsr ≤ 20 kyr“bow shock” PWNe for older pulsars
CXO opt
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Ω Bαlight
cylinderRLC= c/Ω
closedfield lines
E⊥B
nullcharge surfaceΩ.B= 0
polar capγ+B→ e±
outergap
γ+X→ e±
slot gap
pulsar magnetospherepulsar magnetosphereunipolar inductor field from B rotation
extracts charges from the neutron starmgnsph. filled with force-free charge density
Goldreich & Julian ’69acceleration sites in openmgnsph. where
primary charges accelerated to ~10 TeVemit γ photon (curvature rad.)
γ initiate e± cascades
question: are ions alsoaccelerated?
//GJ E⇒ρ≠ρ
B)r(Errrr
∧∧Ω−=
BGJvv⋅Ωε−=ρ 02
2psr m kg for E 3810≈ΩΩ= I&& I
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pulsar windpulsar windretarded potentials => elmgn. wave outside the light cylinderwind = toroidal (wound up) field frozen to an e±- ion plasmaσ ratio = Poynting flux / particle energy flux (Rees & Gunn ’74, Kennel & Coroniti ’84)
σ >> 1 EM wave takes the pulsar energy away (near light cylinder)σ << 1 pulsar energy transferred to wind particles (near terminal shock)
light cylinder
wind γ ∼106
ambiant medium
shocked wind(syn. neb)
contact discontinuity
psw= pext
terminal shockterminal shockterminal shock
B⊥Ω
)mc(vncB
www
w2
111
021
γ
μ=σ
σ+=
σ+=⇒+=
/E
EE
EEEE psrEB
psrwEBwpsr 111
&&
&&&&&
1>>σ 1>>σ
1<<σ
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open questionsopen questions
how are particles accelerated in the magnetosphere?how many secondaries produced in the cascades?
how is the elmgn energy transferred to the particles in the wind?σ >> 1 at the light cylinder, σ = 0.001 - 0.1 at the terminal shock‘silent’ transfer since charges follow B ⇒ syn. radiation <<large equatorial to pole asymmetries (torii and jets)
how is this energy transformed to radiation in the shocked wind?physics of a relativistic shock
how does the wind nebula evolve?early expansion in ‘cold’ SN ejectalater expansion in ‘hot’ ejecta shocked by the SNR reverse shockbow shock confinement from pulsar supersonic motion in SNR or in ISM
applicationsblazar and γ-ray bursts jet formation and relativistic shocksSag A*
« The answer, my friend, is blowing in the wind » (Bob Dylan)
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PWN structurePWN structure
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MHD shock waveMHD shock waveconservations => jump conditions in the shock frame
strong perpendicular shock p2 >> p1: compression ratio X
1.7 kyr old pulsar at 5.2 ± 1.4 kpc, Ėpsr = 1.8 1030 WX-ray jets (12 pc, 0.5 c, long-term variability) and variable knots (0.6c)2 TeV arms ± 25 pc long, radiatively more efficient than the Crab
DeLaney ’06Aharonian ‘05
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Photon index2.27 ± 0.03 ± 0.20
MSH 15-52MSH 15-52
TeV)IR(ISRFCMBe
X)nT.(Be
TeV
TeV
→++
→+±
±− 7110010
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high-energy relic tailshigh-energy relic tails
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Vela tailVela tail
~ 5 pc long tailseen up to 50 TeVE-1.9 ou E-1.5+cutoff
Vela pulsar
ROSATcontours
Preliminary
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PSR B1823-13 - G18.0-0.7PSR B1823-13 - G18.0-0.721.4 kyr old pulsar