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
Image credit: R Hynes
• Soft state quenching
– Role of a disc wind?
• Soft-to-hard transitions
– Compact jets re-established
Image credit: R Hynes
The multiwavelength view of an XRB
• Jets: IR, radio
• Donor: IR,
optical
• Disc: optical,
UV, X-rays
• Corona: X-rays
• Corona/jet
base: g-rays?
Markoff (2007)
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
Disc-dominated
Power-law dominated
Bright
Dhawan et al. (2000)
Faint
Fender, Belloni & Gallo (2004)
Mirabel & Rodriguez (1994),
Fender et al. (1999)
Compact jets in the hard state
Disc-dominated
Bright
Faint
Fender, Belloni & Gallo (2004)
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
Compact jets: morphology
• Jets directly resolved in 3 sources
Rushton et al.
(2012)
• Inferred to exist in all hard-state systems
• Flat/inverted radio spectra
• Radio/X-ray correlation
MAXI J1836-194
GRS 1915+105
Dhawan et al. (2000)
Cygnus X-1
Compact jets: radio polarization
• Polarized emission probes B-field
ordering and orientation
• Few percent polarization detected in 3
sources
• EVPA, B-field aligned with jet axis
MAXI J1836-194
Corbel et al. (2000)
GX 339-4
Cyg X-1
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)
The radio/X-ray correlation
• Lr a Lx0.7
Corbel et al. (2003)
Gallo et al. (2003)
Gallo et al. (2006)
Universality?
• Radio-quiet outliers falling well below correlation
Jonker et al. (2012)
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)
A mix of physical processes?
• Steep slope: has to be radiatively efficient?
Lr a Lx2.1
Transition period
Disc-dominated
Bright
Faint
Fender, Belloni & Gallo (2004)
Power-law dominated
H1743-322
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)
The accretion-ejection connection
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<b<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
Disc-dominated
Bright
Faint
Fender, Belloni & Gallo (2004)
Power-law dominated
Compact jet quenching
• Compact jets quenched
in soft states
• Quenching factor >700
(Coriat et al. 2011)
• Quenching factor >330810 (Russell et al.
2011)
• Possible difference with
AGN (less quenching)
• Role played by disc
winds? (see Neilsen
talk)
Russell et al. (2011)
Jet reactivation
Disc-dominated
Bright
Faint
Fender, Belloni & Gallo (2004)
Power-law dominated
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