Black hole accretion and jet ejection James Miller-Jones Collaborators: Greg Sivakoff, the JACPOT XRB collaboration, Tom Russell, Peter Jonker, Dave Russell

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

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 J

Dhawan et al. (2000) GRS Compact jets: morphology Cygnus X-1 MAXI J 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 Compact jets: radio polarization Cyg X-1 MAXI J 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 L x Corbel et al. (2003) Gallo et al. (2003) Gallo et al. (2006)

The radio/X-ray correlation L r  L x 0.7 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)

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? L r  L x 2.1

Transition period Fender, Belloni & Gallo (2004) Bright Faint Disc-dominated Power-law dominated

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) H

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)

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 > (Russell et al. 2011) Possible difference with AGN (less quenching) Role played by disc winds? (see Neilsen talk) Russell et al. (2011)

Jet reactivation Fender, Belloni & Gallo (2004) Bright Faint Disc-dominated 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 ) Compact radio jets re-ignite on moving from HSS to HIMS