black hole accretion and jet ejection james miller-jones collaborators: greg sivakoff, the jacpot...
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Black hole accretion and jet ejection
James Miller-Jones
Collaborators: Greg Sivakoff, the JACPOT XRB collaboration, Tom Russell, Peter Jonker, Dave Russell
Email: james.miller-jones@curtin.edu.au
Overview
• Disc-jet coupling in X-ray binaries
• Hard states:
– Compact jets– Radio/X-ray correlation
• Hard-to-soft transitions:
– Compact jets quenched– Launching of discrete ejecta
• Soft state quenching
– Role of a disc wind?
• Soft-to-hard transitions
– Compact jets re-established
Image credit: R Hynes
Image credit: R Hynes
The multiwavelength view of an XRB
Markoff (2007)
• Jets: IR, radio• Donor: IR,
optical• Disc: optical,
UV, X-rays• Corona: X-rays• Corona/jet
base: -rays?
Why study XRBs in the radio band?
• Band in which emission is dominated by the jets
• Probe of high-energy processes
• High-resolution imaging
– Resolve jet morphology evolving in real time– Jet collimation, propagation, energetics– Probe accretion-ejection coupling
• Astrometry
– Faint, persistent emission in hard/quiescent state– Model-independent parallax distances– Proper motions (formation mechanisms,
birthplaces)
Jet-disk coupling in accreting black holes
Fender, Belloni & Gallo (2004)
Bright
Faint
Disc-dominated Power-law dominated
Mirabel & Rodriguez (1994), Fender et al. (1999)
Dhawan et al. (2000)
Compact jets in the hard state
Fender, Belloni & Gallo (2004)
Bright
Faint
Disc-dominated Power-law dominated
Compact jets: spectra• Flat or slightly inverted spectra from radio through IR
• Overlapping SSA spectra, we see emission from optical depth 1 at each frequency
• Spectral break (typically mid-IR) provides radiative luminosity of jet
Fender et al. (2000)MAXI J1836-194
Dhawan et al. (2000)
GRS 1915+105
Compact jets: morphology
Cygnus X-1
MAXI J1836-194
• Jets directly resolved in 3 sources
• Inferred to exist in all hard-state systems
• Flat/inverted radio spectra
• Radio/X-ray correlation
Rushton et al. (2012)
Corbel et al. (2000)
GX 339-4
Compact jets: radio polarization
Cyg X-1
MAXI J1836-194
• Polarized emission probes B-field ordering and orientation
• Few percent polarization detected in 3 sources
• EVPA, B-field aligned with jet axis
The radio/X-ray correlation
• Non-linear correlation over 8 decades in Lx
Corbel et al. (2003)
Gallo et al. (2003)
Gallo et al. (2006)
Two tracks
• Clustering analysis shows evidence for two distinct clusters
• Bayesian regression of the two clusters shows different slopes
Gallo et al. (2012)
Gallo et al. (2012)
Efficient vs inefficient accretion?• Transition between radio-quiet and radio-loud branches
Coriat et al. (2011)
Efficient vs inefficient accretion?• Transition between radio-quiet and radio-loud branches
Ratti et al. (2012)
Transition
• X-ray emission rises
• X-ray hardness, fractional variability decrease
• Appearance of QPOs
• Compact jet quenching
• Major radio flare
• Launching of discrete ejecta
Miller-Jones et al. (2012)
H1743-322
Spectral signatures of ejection
• Use VLBA proper motions to determine ejection date
• Does the “Unified Model’ hold?
– As far as we can tell– Additional radio quench phase
Miller-Jones et al. (2012)
Miller-Jones et al. (2012)
Timing signatures of ejection
• What happens in the accretion disc to cause the switch?
– X-ray spectral state transition– Type C QPOs disappear from power spectrum– Fractional rms variability drops
Miller-Jones et al. (2012)
The transient ejecta
• Note delay between derived ejection date and when transient jets appear
– Ejection precedes radio quenching
– Time for ejecta to become optically thin at radio frequencies?
– Time for internal shocks to form within the jet?
Miller-Jones et al. (2012)
Comparison of different outbursts
• Does the ejection always happen at the same hardness?
– No; different in two outbursts of the same source
Miller-Jones et al. (2012)
Comparison of different outbursts
• Jet ejecta have different speeds in the two outbursts
– Proper motions 3.7 ± 0.7, 3.3 ± 0.8 mas/d in 2009– Corresponds to 0.19<<0.28– Compare with 21.2 ± 1.4, 13.3 ± 0.6 mas/d in 2003 (after
deceleration)
• Black hole spin unlikely to have changed between outbursts: more likely to be mass accretion rate
• 2003 outburst significantly brighter
– Is jet speed correlated with outburst luminosity?
Quenched jets in the soft state
Fender, Belloni & Gallo (2004)
Bright
Faint
Disc-dominated Power-law dominated
Compact jet quenching
• Compact jets quenched in soft states
• Quenching factor >700 (Coriat et al. 2011)
• Quenching factor >330-810 (Russell et al. 2011)
• Possible difference with AGN (less quenching)
• Role played by disc winds? (see Neilsen talk)
Russell et al. (2011)
Jet re-activation
• When do compact jets re-ignite in the radio band?
– On moving from HSS to HIMS
• No VLBA detection after main outburst; emission location unconfirmed
• OIR jets known to switch on only after return to LHS
• Gradual evolution of jet power?
• Remnant optically thin emission?
Miller-Jones et al. (2012)
Summary
• Compact jets ubiquitous in hard states of BH XRBs
• Magnetic fields oriented along jet axis
• Correlation between radio, X-ray emission
• Separate branches, with transition between them
• Different spectral slopes
• Jet ejection events correlate with X-ray spectral and timing changes
• Causal sequence not yet established
• Different outbursts have different jet speeds
• Quenching of radio emission in soft states (factor 102-103)
• Compact radio jets re-ignite on moving from HSS to HIMS
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