The Crab Impact
description
Transcript of The Crab Impact
Frascati 15 vii 2012
The Crab Impact
Roger BlandfordYajie Yuan
KIPACStanford
Frascati 2
Wind, Shock, Jet, Torus (not Pulsar)? • Pulsar:
– F~50PV, I ~ 200 TA;– LEM ~ 1038 erg s-1 ~ 0.3 Lneb
• Nebula:– U~ 3 x 1049 erg; Beq~0.3mG– 3 Msun filaments
• Wind:– B~0.3(R/r)s1/2 mG– Striped? Dissipation?– Relativistic beaming/sector structure vs power– L/LEM<DW/4p<tvar/100d in flow model.
• Hard to satisfy!
• Ring/Shock?:– R~ 100 lt d ~ 2 x 109 Rlc
– Current Sheet? Dissipation?• Jets
– >0.1 R?, B~0.3(R/r)I14 mG– Pinch? Dissipation?
1 lt hr = 3 masLarmor radius= 60g9B-3
-1mas 5 vii 2012
W
SJ
TP
=10,000mas
Frascati 3
Flare Electrodynamics
5 vii 2012
High energy particles carry the current?Electron “synchrotron” radiation in uniform B• E~2B-3
-1/2PeV; Ne~4 x 1038(DW/4p); Ue~1042B-3-3/2 erg;
• rL~3B-3-3/2 lt d; tcool~12B-3
-3/2 hr ~ 12o
• Compensate loss with E||~140Vm-1~9B-3-1/2 PVrL
-1~ 5B• (Ue/3Pneb)1/3~B-3
rL; (Uf/3Pneb)1/3~10B-3 rL if isotropic
• tvar > 1 d!
0.01Lneb
tvar~1-10hr
Frascati 4
Radiative shocks
5 vii 2012
s=1
s=100CylindricalAngle
• No reflection; downstream dissipation• g9=3; B=1mG• Planar, cylindrical, ellipsoidal shocks• Time-dependent shocks• Relativistic shock motion• Receding brightest• Understand kinematics
s=100SphericalMoving
Denver 5
Particle drifts and current
28 vi 2012
Normal approach is to analyze particle orbits and deduce currentsCan also start from static equilibrium and understand what is happening
Curvature perpendicular magnetization gradient ExB
Orbit, fluid approaches to Ohm’s law perpendicular to field are identicalParallel current requires additional physics eg wave-particle scatteringA closely related approach is double adiabatic theory
€
P⊥ = 12 ∫ dpp⊥v⊥ f ∝ ρp⊥
2 ∝ ρB ( NR)
P|| = ∫ dpp||v|| f ∝ ρp||2 ∝ ρ 3B−2 ( NR)
Complete?
Incomplete?
Frascati 6
Pinch Equilibrium?• Resistance in line current
– Current carried by high energy particles
– Resistance due to radiation reaction– Pairs undergo poloidal gyrations
which radiate in all directions– Relativistic drift along direction of
current - Jet!!– Compose current from orbits self-
consistently– Illustration of Poynting’s theorem!– Variation intrinsic due to instability
5 vii 2012
jBf
r
X
E
€
E⋅ j = −∇⋅N
jz =1
cμ0
∇⋅ E
< j >=Prr
B2
dBdϖ
+Pφφ
Bϖ
CIFAR 7
Formalism
1 iv 2011
x(t), u, a, j
x
r
€
fres =2q2
3( j + j.uu)
A = −quξ.u
F =q
3ξ.u[ξ.ua∧ξ + (1+ ξ.a)ξ∧u]
T =q2
64πξ.u[(a.aξ.u2 − (1+ ξ.a)2)ξ ⊗ξ − (1+ ξ.a)ξ.u(ξ ⊗u + u⊗ξ) + ξ.u2(ξ ⊗a + a⊗ξ +
12
g)]
t
dawn
dusk
€
Dp = d∫ ∑• T
Pem
Pres
1D Jerk
Take limit to demonstrateenergy flow.
Broader
30 v 2012 Ginzburg 8
2x1050erg s-1 isotropicBreaks due to recombination radiation?
Marscher
Radio Monitoring (OVRO 40m)
• ~1500 sources• Radio and g-ray active• Spectrum, polarization
30 v 2012 Ginzburg 9
Max-Moerbeck etal
Rapid MAGIC variation• PKS
1222+21– 10 min
• MKN 501– 5 min
• PKS 2155-304– 2 min Aharonain
(Aharonian30 v 2012 Ginzburg 10
PKS 1222+21 (Aleksik et al)
How typical?How fast is GeV variation?
3C 279: multi-l observation of g-ray flare
• ~30percent optical polarization => well-ordered magnetic field• t~ 20d g-ray variation => r~g2ct ~ pc or tdisk?• Correlated optical variation?
=> common emission site• X-ray, radio uncorrelated
=> different sites• Rapid polarization swings
~200o => rotating magnetic field in dominant part of source
Abdo, et al Nature, 463, 919 (2010)
r ~ 100 or 105 m?
30 v 2012 11Ginzburg
PKS1510+089
(Wardle, Homan et al)
30 v 2012 Ginzburg 12
z=0.36• Rapid swings of
jet, radio position angle• High polarization ~720o (Marscher)• Channel vs Source• TeV variation (Wagner / HESS)• EBL limit• rmin ; rTeV>rGeV (B+Levinson)
bapp=45