Into the Engine:Into the Engine:GRMHD SimulationsGRMHD Simulations

Jonathan McKinneyJonathan McKinney

Stanford/KIPACStanford/KIPAC

Black Hole Accretion Black Hole Accretion SystemsSystems

Mirabel & Rodriguez (Sky & Telescope, 2002)

1038erg/s

M~10M¯

1044erg/s

M~107M¯

1052erg/s

M~3M¯

EM Model (Lyutikov & Blandford 2003)

Taylor et al. 2004

Fireball Model (Sari, Piran, Meszaros, Rees >1993)

GRB JetsGRB JetsIssues:

•Launch: - vs. MHD Jets

•Jet: Fireball vs. EM

•Prompt: Shocks vs. EM dissipation

AGN JetsAGN JetsJet Issues:

•Some Dark (non-dissipative?)

•Origin of FRI vs. FRII Classes?

•Radio Loud-Quiet Dichotomy?

•Blazars (-ray and TeV Emission?)

•Implication for GRBs?

3C31

Pictor A

M87

Mrk501

Cygnus-A

Junor/Biretta/Walker

Example Solutions to Example Solutions to AGN DichotomyAGN Dichotomy

Changes in Field GeometryChanges in Field Geometry Non-Dipolar FieldsNon-Dipolar Fields (Beckwith/McKinney ‘09) (Beckwith/McKinney ‘09)

Changes in Jet ConfinementChanges in Jet Confinement Triggers Magnetic SwitchTriggers Magnetic Switch (Meier et al. ’97, Komissarov (Meier et al. ’97, Komissarov

2009)2009)

Variation in amount of BH/Disk Magnetic FluxVariation in amount of BH/Disk Magnetic Flux Flux trappingFlux trapping (Reynolds 06, Garafalo ‘09) (Reynolds 06, Garafalo ‘09)

Magnetically-dominated disk Magnetically-dominated disk (Igumenshchev ‘09)(Igumenshchev ‘09)

Difference in Disk ThicknessDifference in Disk Thickness (Meier ’01) (Meier ’01)

Application to GRBs?Application to GRBs? (flux trapping: Proga ‘06) (flux trapping: Proga ‘06)

BH X-Ray BinariesBH X-Ray Binaries

Belloni et al.Orosz

Questions:•What determines the Spectral (and Temporal) States?•How are X-ray binary states related to AGN and GRBs?

Mirabel & Rodriguez

Disk-Jet Coupling EffectsDisk-Jet Coupling Effects

Blandford & Payne ‘82 MacDonald & Thorne ‘82

BZ77

Role of Large-Scale vs. Small-Scale Magnetic Fields?Role of Large-Scale vs. Small-Scale Magnetic Fields? Disk dominates BH in powering jet?Disk dominates BH in powering jet? (Ghosh & Abramowicz 1997;Livio, Ogilvie, Pringle 1999)(Ghosh & Abramowicz 1997;Livio, Ogilvie, Pringle 1999)

Weak Magnetic Field Threads BH?Weak Magnetic Field Threads BH? (Ghosh & Abramowicz 1997;Livio, Ogilvie, Pringle 1999)(Ghosh & Abramowicz 1997;Livio, Ogilvie, Pringle 1999)

Jet Power Jet Power // a a22 (weak dependence)? (weak dependence)? (Blandford & Znajek 1977 vs. McKinney 2005)(Blandford & Znajek 1977 vs. McKinney 2005)

3D GRMHD Simulations3D GRMHD Simulations

Issues:•Jet from Disk or BH?

•Unstable to Turbulence in Disk?

•Unstable to Accreting Disordered Field?

Dipolar Quadrupolar

•Quadrupolar Field Jet Fails

•Magnetic field geometry crucially determines existence of jet

Fully 3D GRMHD Jet Simulations

McKinney & Blandford (2009)

•Dipolar Field Jet Succeeds

•Suggests jets require accretion of organized field

Fully 3D GRMHD Jet Simulations

McKinney & Blandford (2009)

X-Ray Binaries: Origin of X-Ray Binaries: Origin of States?States?

Igumenshchev (2009) McKinney & Blandford (2009)

Dipolar

Quadrupolar

No Ordered Field

McKinney & Gammie (2004)

DeVilliers, Hawley, Krolik (2003-2004)

CORONA: MA~EM

FUNNEL: EM dominated

JETS: Unbound, outbound flow

Poy

ntin

g Je

t“M

atte

r” J

et

BH Engine Flow StructureBH Engine Flow Structure

Field becomes super-Field becomes super-equipartition for high equipartition for high

spinspin

Kom

issa

rov

& M

cKin

ney

(20

07)

McKinney (2005)Tchekhovskoy, Narayan, McKinney (2010)

Jet Propagation Stability: Jet Propagation Stability: KinkKink

Kruskal-Shafranov non-rel. criterionKruskal-Shafranov non-rel. criterion

Tomimatsu (2001) ~rel. criterionTomimatsu (2001) ~rel. criterion

McKinney (2006) Narayan et al. (2009)

L

R

RL

j

zB

|m|=1 most dangerous: Center-of-mass shifted|m|=1 most dangerous: Center-of-mass shifted

Expansion & Finite Mass-loading: Jet goes Expansion & Finite Mass-loading: Jet goes out of causal contactout of causal contact

Narayan et al. (2009) rel. criterionNarayan et al. (2009) rel. criterion

•Dipolar Field Jet Succeeds:

•Relativistic Rotation, Expansion, Non-linear Saturation

DipolarField

Applications to GRBs 1Applications to GRBs 1Setup:

•Collapsar Model

•2D GRMHD

•Start with BH and collapsing star

•Realistic EOS

•Neutrino Cooling (no heating)

•Strong and Ordered Magnetic Field

Result:

•BZ-effect drives MHD jet

•Still no high Lorentz factors

•3D and resolution needed to study boundary instabilities

Komissarov & Barkov (2008-2009)

Applications to GRBs 2Applications to GRBs 2Problem:

•Ultrarelativistic motion: ~ 400 (Lithwick & Sari 2001, Piran 2005)

•Afterglow Breaks: » 2-20

•Standard MHD Jet Models give » 1

Any Resolution?

•Stellar Break-Out Rarefaction

Light curve modeling

givesµ =2

{ 10

”Achromatic break” in the light curve when

(µ)t ≃ 1

1 day 10 days 100 days

Tchekhovskoy, Narayan, McKinney (2010)

3210Jet Break-OutJet Break-Out

¡0:2r¤ 0:2r¤BH BH

star

= 100µ =

0.02

µ = 2

= 500µ =

0.04

µ = 20

Tchekhovskoy, Narayan, McKinney (2010)

log()

Komissarov et al. (2010)

Effects of Time-Effects of Time-VariabilityVariability Idea:Idea:

Time-variable Jet leads to Time-variable Jet leads to magnetized jet bubble separated by magnetized jet bubble separated by a near-vacuum if envelope cannot a near-vacuum if envelope cannot relax fast enough to fill-in hole left relax fast enough to fill-in hole left by the jetby the jet

Problem:Problem: Compact object + disk generate Compact object + disk generate

wind and fills-in hole when jet is wind and fills-in hole when jet is turned offturned off

No forward rarefaction would occurNo forward rarefaction would occur Solution: Transient suppression of Solution: Transient suppression of

jet+wind by ram pressure of fresh jet+wind by ram pressure of fresh in-falling materialin-falling material

Granot et al. (2010) & Lyutikov Granot et al. (2010) & Lyutikov (2010)(2010)

GRMHD Simulations of GRMHD Simulations of Thin DisksThin Disks

Sha

fee, M

cKinney, et al. (2008)

PA

z

R

Results:

1) Thin Disk theory (Novikov & Thorne 1973) holds fairly well as long as H/R. 0.07

2) and shear stress not good indicators of dissipation or transport near ISCO or horizon

3) Assumed initial Magnetic Field controls level of deviations from Thin Disk Theory

Pen

na, McK

inney, et al. (2010)

Review:Review: BH Driven Jet becomes Relativistic if Ordered BH Driven Jet becomes Relativistic if Ordered

FieldField GRB Jets: Stellar Break-out Leads to GRB Jets: Stellar Break-out Leads to ÀÀ 1 1 »» 20 20

Disk Driven Wind-Jet is Weakly RelativisticDisk Driven Wind-Jet is Weakly Relativistic Mass-Loaded by Disk TurbulenceMass-Loaded by Disk Turbulence

Jet Stability Maintained by (e.g.)Jet Stability Maintained by (e.g.) Relativistic Rotation of Field Lines & Expansion of JetRelativistic Rotation of Field Lines & Expansion of Jet Non-linear SaturationNon-linear Saturation

Standard (Novikov-Thorne) Thin Disk theory Standard (Novikov-Thorne) Thin Disk theory holdsholds Much prior work on GRB accretion solutions are ~ Much prior work on GRB accretion solutions are ~

validvalid