The X-ray Universe 2008, Granada, May 27-30 2008

A Jet-Emitting Disk model for the A Jet-Emitting Disk model for the microquasar broad band microquasar broad band

emissionemissionG. HenriG. Henri

Coll. P.O Petrucci, J. Ferreira, C. FoellmiColl. P.O Petrucci, J. Ferreira, C. FoellmiLaboratoire d ’Astrophysique de Grenoble, FranceLaboratoire d ’Astrophysique de Grenoble, France

The X-ray Universe 2008, Granada, May 27-30 2008

Accretion and ejectionAccretion and ejection

X-ray binaries show strong spectral variability

Low-hard

•hot corona

•disk emission weak or absent

High soft

•disk-dominated

•non thermal power-law

Grove et al ‘98

The X-ray Universe 2008, Granada, May 27-30 2008

Hysteresis cycleHysteresis cycle

.

Hardness-intensity plots show characteristic hysteresis cycles

At least two parameters : M and…… ?.

e.g. GX339-4 Belloni et al. ‘05

The X-ray Universe 2008, Granada, May 27-30 2008

« Jet-line » flaring events« Jet-line » flaring events

Compact (optically thick) jets associated with low-hard states

Relativistic flares (optically thin) generally associated with luminous « Very High states » when crossing a « jet line » (Fender et al. ‘04)

Dhawan et al. 2000

(Mirabel & Rodriguez 1994)superluminal velocities

e.g. GRS 1915+105

The X-ray Universe 2008, Granada, May 27-30 2008

Spectral transitions Spectral transitions

GRS 1915+105 .

Flaring events associated with the disappearance of the disk emission and hardening spectra

e.g. Mirabel et al., 1998

Correlations betwen X and radio

(Corbel et al. 2003; Gallo et al. 2004…

The X-ray Universe 2008, Granada, May 27-30 2008

A Jet Emitting Disk model :general A Jet Emitting Disk model :general picturepicture

Inner accretion disk emitting a Jet by a MHD centrifugal process

Outer Standard accretion disk (SAD)

Flaring relativistic jets explained by pair creation events (~ AGNs)

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Characteristic transition radius rj

The X-ray Universe 2008, Granada, May 27-30 2008

The MHD Jet Emitting DiskThe MHD Jet Emitting Disk

Baryonic jet can be emitted from the accretion disk through MHD mechanism (Blandford-Payne 1982, Ferreira et al., 1997, 2004)

B field extracts angular momentum and power from the JED (Jet Emitting Disk)

Powerful, but only mildly relativistic (0,5 - 0,9 c)

The X-ray Universe 2008, Granada, May 27-30 2008

EnergeticsEnergetics

Jets extract a fair part of the accretion energy

€

PjetPacc

= qΛ

1+ ΛWhere

€

Λ = MHD torqueViscous torque

~hr

⎛ ⎝ ⎜

⎞ ⎠ ⎟−1

~ 10 to100

€

q ~ 0.5 to1

Jet power -> underluminous disks can « apparently » disappear~ ADAF but energy channelled in jets, not below the horizon

Stable solutions can exist only close to equipartition

If magnetization parameter

€

μ = pBpgas + prad

= 0.1 to1

The X-ray Universe 2008, Granada, May 27-30 2008

Magnetic transitionsMagnetic transitions

In the outer standard disc

€

Bz ∝ r−3/2

ptot ∝ r−1/2

(Jet Emitting Disc)(Standard Accretion Disc)

SAD JED when µ ~ 1

JED SAD when µ ~ 0.1

Pmag/Ptot

rrtr

1

SADJED

0.1

ASSUMPTIONS

µ if r

In the inner JED µ ~ Constant (adjusted by the MHD structure)

The X-ray Universe 2008, Granada, May 27-30 2008

Hysteresis cyclesHysteresis cycles

Petrucci et al, MNRAS 2008

The X-ray Universe 2008, Granada, May 27-30 2008

JED structureJED structure

Thermal JED structure must be determined self-consistently

Simple approximations * isothermal vertical structure

* cooling processes : bremsstrahlung, synchrotron, comptonization.

* heating process = part of accretion energy

Non-linear dependance of heating on

€

Λ ~hr

⎛ ⎝ ⎜

⎞ ⎠ ⎟−1

~vKcs

Balance solved numerically

The X-ray Universe 2008, Granada, May 27-30 2008

Multivalued solutionsMultivalued solutions

Bremsstr. Bremsstr.Synchr.

Synchr.

Compt.

Cold solution : standard disk-likeHot solution : corona-like

Qheat

Qheat

The X-ray Universe 2008, Granada, May 27-30 2008

Radiative transitions

The X-ray Universe 2008, Granada, May 27-30 2008

Example of SED

Depends on radial structure, complicated with multivalued solutions and variability…

still in progress….

Spectral Energy Distributions

The X-ray Universe 2008, Granada, May 27-30 2008

Ejection of relativistic components

In situ generation of pair plasma in the inner MHD funnel (H.& Pelletier 91, Marcowith et al. ‘95)

Produced through gamma-ray emission• Injection of some relativistic particles• X-ray and gamma-ray emission by IC

and/or SSC• annihilation forms new pairs• Continuous reacceleration by MHD

turbulence necessary for a pair runaway to develop.

• Limited by the free energy available: saturation must occur at some point.

• Intermittent production possible and even probable !

hvs X,e+e-

2-flow model for AGNs

The X-ray Universe 2008, Granada, May 27-30 2008

Time dependant flaresTime dependant flares

See Boutelier’s poster (#G4) for the PKS2155-304 case

TeV flux

Pair production

X-ray/optical

The X-ray Universe 2008, Granada, May 27-30 2008

• Density n0(r)• Temperature T0(r)

+ n(r,t)+ T(r,t)

rin

rtr

Hard X

UV/Soft X

Generation of low frequency QPO

The X-ray Universe 2008, Granada, May 27-30 2008

Monte Carlo SimulationsMonte Carlo Simulations

• Vertical optical 0 = 1.4• Temperature T0=100 keV• rtr=50 rg, cs=(kT0/mp)0.5~0.01c

rin

rtr

SED

PDS resonances

cs/rtr

White noise

Energy (keV)

RM

S

Cabanac PhD thesis

The X-ray Universe 2008, Granada, May 27-30 2008

ConclusionsConclusions

A magnetically dominated, inner jet emitting disk can provide a good framework to understand

•Spectral changes

•Correlation X-radio

•Variability, QPO

Complicated interplay between accretion rate, magnetic transitions , radiative instabilities .. (but reality IS complex ! )

•Work in progress to compare with detailed spectra and variability.