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The X-ray Universe 2008, Granada, May 27-30 2008 A Jet-Emitting Disk model for the microquasar broad band emission G. Henri Coll. P.O Petrucci, J. Ferreira, C. Foellmi Laboratoire d ’Astrophysique de Grenoble, France
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The X-ray Universe 2008, Granada, May 27-30 2008 Accretion 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
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The X-ray Universe 2008, Granada, May 27-30 2008 Hysteresis cycle. Hardness-intensity plots show characteristic hysteresis cycles At least two parameters : M and…… ?. e.g. GX339-4 Belloni et al. ‘05
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The X-ray Universe 2008, Granada, May 27-30 2008 « 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) superlumina l velocities e.g. GRS 1915+105
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The X-ray Universe 2008, Granada, May 27-30 2008 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…
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The X-ray Universe 2008, Granada, May 27-30 2008 A Jet Emitting Disk model :general picture 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) Characteristic transition radius r j
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The X-ray Universe 2008, Granada, May 27-30 2008 The 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)
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The X-ray Universe 2008, Granada, May 27-30 2008 Energetics Jets extract a fair part of the accretion energy Where 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
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The X-ray Universe 2008, Granada, May 27-30 2008 Magnetic transitions In the outer standard disc (Jet Emitting Disc) (Standard Accretion Disc) SAD JED when µ ~ 1 JED SAD when µ ~ 0.1 P mag /P tot r r tr 1 SAD JED 0.1 ASSUMPTIONS µ if r In the inner JED µ ~ Constant (adjusted by the MHD structure)
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The X-ray Universe 2008, Granada, May 27-30 2008 Hysteresis cycles Petrucci et al, MNRAS 2008
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The X-ray Universe 2008, Granada, May 27-30 2008 JED 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 Balance solved numerically
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The X-ray Universe 2008, Granada, May 27-30 2008 Multivalued solutions Bremsstr. Synchr. Compt. Cold solution : standard disk-like Hot solution : corona-like Q heat
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The X-ray Universe 2008, Granada, May 27-30 2008 Radiative transitions
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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
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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 ! 2-flow model for AGNs
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The X-ray Universe 2008, Granada, May 27-30 2008 Time dependant flares See Boutelier’s poster (#G4) for the PKS2155-304 case TeV flux Pair production X-ray/optical
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The X-ray Universe 2008, Granada, May 27-30 2008 Density n 0 (r) Temperature T 0 (r) + n(r,t) + T(r,t) r in r tr Hard X UV/Soft X Generation of low frequency QPO
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The X-ray Universe 2008, Granada, May 27-30 2008 Monte Carlo Simulations Vertical optical 0 = 1.4 Temperature T 0 =100 keV r tr =50 r g, c s =(kT 0 /m p ) 0.5 ~0.01c r in r tr SED PDS resonances c s /r tr White noise Energy (keV) RMS Cabanac PhD thesis
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The X-ray Universe 2008, Granada, May 27-30 2008 Conclusions 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.
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