(how) do spinning holes make jets?bond/cifar/agm12/cifar12talks/blandford.pdf · (how) do spinning...
TRANSCRIPT
5 iv 2012 CIFAR 1
(How) Do Spinning Holes make Jets?
Roger Blandford, KIPAC
Stanford with
Jonathan McKinney (KIPAC, Maryland) Sasha Tschekovskoy (Princeton)
Nadia Zakamska (JHU)
22 iv 2010 Sackler Lecture Princeton
Cygnus A
3C31
3C75
Extragalactic Jets
Pictor A
M87
NGC 326
5 iv 2012 CIFAR
Pictor A
Current Flow Nonthermal emission is ohmic dissipation of current flow?
Electromagnetic Transport 1018 not 1017 A DC not AC No internal shocks New particle acceleration mechanisms
Pinch stabilized by velocity gradient?
Equipartition in core
Wilson et al
3
5 iv 2012 CIFAR 4 832AGN+268Candidates+594Unidentified!
3C454.3
5 iv 2012 CIFAR 5
2x1050erg s-1 isotropic Breaks due to recombination radiation?
Marscher
Radio Monitoring (OVRO 40m)
• ~1500 sources • Radio and γ-ray active • Spectrum, polarization
5 iv 2012 CIFAR 6
Max-Moerbeck etal
Rapid MAGIC variation
• PKS 1222+21 – 10 min
• MKN 501 – 2min?
• PKS 2155-304 – “Few hr”?
5 iv 2012 CIFAR 7
PKS 1222+21 (Aleksik et al)
How typical? How fast is GeV variation?
3C 279: multi-λ observation of γ-ray flare • ~30percent optical polarization
=> well-ordered magnetic field • τ~ 20d γ-ray variation => r~γ2cτ ~ pc or τdisk? • 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?
5 iv 2012 8 CIFAR
PKS1510+089 (Wardle, Homan et al)
5 iv 2012 CIFAR 9
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)
βapp=45
Jansky VLA (New Mexico)
5 iv 2012 CIFAR 10
27 antennae, 1-50GHz (+0.08GHz) 10xsensitivity… 50 mas resolution
SS433 and the W50 nebula
Chandler Outflows, Winds, and Jets Workshop, March 2012
11
ALMA First results
5 iv 2012 CIFAR 12
Atacama desert 5km high 66 telescopes, 300µ- 1cm eventually ~ 5mas resolution
5 iv 2012 13 CIFAR
B
M
Ω Rules of thumb:
Φ ∼ B R2 ; V ~ Ω Φ; I~ V / Z0; P ~ V I
PWN AGN GRB B 100 MT 1 T 1 TT Ω/2 10 Hz 10 µHz 1 kHz R 10 km 10 Tm 10 km V 3 PV 300 EV 30 ZV I 300 TA 3 EA 300 EA P 100 XW 1 TXW 10 PXW
Unipolar Induction
UHECR!
€
m =m0
1− β2; β =Ωm < 2−1/ 2
5 iv 2012 CIFAR
Intermediate Mass Supply
• Thin, cold, steady, slow, radiative disk • Specific energy e = -Ωl/2
€
G − ′ M = const ≈ 0dLdr
=d(ΩG − ′ M e)
dr≈ 3 ′ M de
drG
Energy radiated is 3 x the local energy loss 14
5 iv 2012 CIFAR
Low, High Mass Supply • M’<<M’E, tenuous flow cannot heat electrons and cannot cool • M’>>M’E, dense flow traps photons and cannot cool • Thick, hot, steady, slow, adiabatic disk • Bernoulli function: b =e+h
€
G − ′ M ≈ 0ΩG − ′ M b ≈ 0⇒ b ≈ −2e > 0
G
Energy transported by torque unbinds gas => outflow
ADiabatic Inflow-Outflow Solution 15
5 iv 2012 CIFAR 16
Ω
x
.
Dipolar or Quadrupolar?
Even field Odd current
Lovelace, Camenzind, Koide, RB
Odd field Even current
Also prograde vs retrograde?
5 iv 2012 CIFAR 17
“Observing” Simulated Jets Synchrotron Radiation
€
IνΩ(ν,to) = dzδ 2 j'ν 'Ω'∫ (ν /δ,to)e− dzδ −1κ '(ν /δ ,to )∫
δ =1
γ(1−Vz)
Sν (ν,to) =1ad2
dxdyI∫νΩ(ν,to)
5 iv 2012 CIFAR 18
• We know P’, B’, N’, V on grid • Work in jet frame • Rotate spatial grid so that observer along z direction • Shear in t – z space introducing to=t-z
• Make emission model • eg j’ ~ P’ B’3/2ν’-1/2; κ’∼ P’B’2ν’-3
• Polarization – perpendicular to projected field in cm frame
t
z
to
z’
z
Vß
“Observing” Simulated Jets Inverse Compton Radiation
• Work in jet frame • Compute incident radiation along all rays from earlier observer times
• Compute jνΩ directly
5 iv 2012 CIFAR 19
Observer s θ
r
[r-s,to-s(1-cosθ)]
z
“Observing” Simulated Jets Pair Opacity
5 iv 2012 CIFAR 20
€
κ = dsdΩdνNνΩ( r − s ∫ ,to − s(1− cosφ),ν )σPP (1− cosφ)
• External and internal radiation • Internal radiation varies
5 iv 2012 CIFAR 21
Disk
Light
Optical emission from jet with γ ~ 3-4
Zakamska, RB & McKinney in prep
Quivering Jets • Observe γ-rays (and optical in 3C279) • Gammasphere τγγ~1, 100-1000m ~ Eγ • Rapid variation associated with convected flow of features (2min in Mkn 501)
• Slow variation associated with change of jet direction on time scale determined by dynamics of disk (precession?) or limited by inertia of surrounding medium or both as with m=1 wave mode. 5 iv 2012 CIFAR 22
5 iv 2012 CIFAR 23
Total Flux and Degree of Polarization
Summary
5 iv 2012 CIFAR 24
• New observations of AGN and stellar relativistic jets • Fermi, MAGIC, optical polarimetry, JVLA, ALMA…
• 3D Black Hole MHD simulations possible for >106 m • Efficient energy extraction • Powerful winds • Jet Disk Oscillations
• “Observe” simulated relativistic jets • Radio, g-rays, optical polarization
Dynamical elements • Bulk flow • Shocks • Shear flow • Plasmoids, flares, minijets,magnetic rockets…
– Lorentz boosting • Precession
– Disk – m=1 instability
• Turbulence
5 iv 2012 CIFAR 25
Each of these elements changes the field and the particles
Pair vs Ion Plasmas
• Pairs must be heavily magnetized to avoid radiative drag
• Circular polarization, Faraday rotation/pulsation
• Expect? pairs, field todecrease, ions to increase along jet
5 iv 2012 CIFAR 26
5 iv 2012 27 CIFAR
Particle acceleration in high σ environments
• Internal shocks are ineffectual • Reconnection can be efficient
– E>B?? • Shear flow in jets
– Full potential difference available particles accelerated when undergo polarization drift along E
– UHECR (eg Ostrowski & Stawarz, 2002)
• Fast/intermediate wave spectrum – Nonlinear wave acceleration(Blandford 1973…)
• Mutual evolution of wave cascade and particle distribution function – Charge starvation (eg Thompson & Blaes 1997)
• Force-free allows E>B - catastrophic breakdown
Particle Acceleration
5 iv 2012 CIFAR 28
• S-C-1 transition quite high in BLLacs • “Theoretically” Eγ<α-1 mec2~60MeV
• cf Crab Nebula, UHECR • Large scale electric fields • Lossy coax?? • Follow particle orbits. • Which particles carry the current • Is the momentum elctromagnetic?
5 iv 2012 CIFAR 29
Faraday Rotation
Broderick & McKinney
Signature of toroidal field/axial current
Rotation from sheath
Observations ???
Simulation
5 iv 2012 CIFAR 30
Telegraphers’ Equations
5 iv 2012 CIFAR 31
Relativistic Reconnection
McKinney & Uzdensky
• High σ flow • Hall effects may save Petschek mechanism • Anomalous resistivity? • Also for AGN Petschek
GRBs?
5 iv 2012 CIFAR 32
Inhomogeneous Sources • Radio synchrotron photosphere, r ~ λ
– Doppler boosting • Compton gammasphere, r ~ E?
– Internal, external radiation – Test with variability, correlation
• Electron acceleration – >100 TeV electrons
5 iv 2012 CIFAR 33
S
ν E
S C-1
Summary • Protostars->GRBs->Quasars • Location, mechanism, collimation, origin…? • FGST+TeV+multi-λ observations of blazars • Major monitoring campaigns • Rotating polarization, rapid variation • GRMHD simulations answering basic questions
about flows, dynamics • “Observations” of simulations now possible to
(in)validate simple phenomenological models and test against data and “best” examples.
5 iv 2012 CIFAR 34
3D GRMHD Simulations • >105m Kerr-Schild, HARM, 512x768x64
– Quasi-steady state • Build up flux –back reaction
– Thick spinning disks, suppress MRI – Dipolar (not quadrupolar) makes jets
• Efficient extraction of spin energy-> jets – Prograde (not retrograde) more efficient
• Wind outflows – Poorly collimated, slow
• QPOs, – ~70m, a~ 0.9; Q~100 (jet) ~3 (disk)
• Strong intermittency – Helical instability m=1
5 iv 2012 CIFAR 35
McKinney, RB; McKinney, Tschekovskoy, RB
Tschevoskoy et al Talk on MONDAY