(how) do spinning holes make jets?bond/cifar/agm12/cifar12talks/blandford.pdf · (how) do spinning...

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

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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

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2x1050erg s-1 isotropic Breaks due to recombination radiation?

Marscher

Radio Monitoring (OVRO 40m)

•  ~1500 sources •  Radio and γ-ray active •  Spectrum, polarization

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Max-Moerbeck etal

Rapid MAGIC variation

•  PKS 1222+21 –  10 min

•  MKN 501 –  2min?

•  PKS 2155-304 –  “Few hr”?

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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?

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PKS1510+089 (Wardle, Homan et al)

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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)

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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

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Atacama desert 5km high 66 telescopes, 300µ- 1cm eventually ~ 5mas resolution

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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

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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

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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

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Ω

x

.

Dipolar or Quadrupolar?

Even field Odd current

Lovelace, Camenzind, Koide, RB

Odd field Even current

Also prograde vs retrograde?

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“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)

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• 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

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Observer s θ

r

[r-s,to-s(1-cosθ)]

z

“Observing” Simulated Jets Pair Opacity

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€

κ = dsdΩdνNνΩ( r − s ∫ ,to − s(1− cosφ),ν )σPP (1− cosφ)

• External and internal radiation • Internal radiation varies

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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

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Total Flux and Degree of Polarization

Summary

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• 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

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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

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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

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• 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?

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Faraday Rotation

Broderick & McKinney

Signature of toroidal field/axial current

Rotation from sheath

Observations ???

Simulation

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Telegraphers’ Equations

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Relativistic Reconnection

McKinney & Uzdensky

• High σ flow • Hall effects may save Petschek mechanism • Anomalous resistivity? • Also for AGN Petschek

GRBs?

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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

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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.

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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

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McKinney, RB; McKinney, Tschekovskoy, RB

Tschevoskoy et al Talk on MONDAY