1. The Jet Acceleration and Collimation Probe of Transient X-ray Binaries (JACPOT XRB): Investigating accretion disk-radio jet coupling across the stellar mass scale James Miller-Jones on behalf of the JACPOT XRB collaboration Web: http://www.astro.virginia.edu/xrb_jetshttp://www.astro.virginia.edu/xrb_jets Email: james.miller-jones@curtin.edu.au

2. Jet Acceleration and Collimation Probe of Transient X-ray Binaries (JACPOT XRB) James Miller-Jones (ICRAR-Curtin), Greg Sivakoff (U Virginia), Ron Remillard (MIT), Diego Altamirano (U Amsterdam), Vivek Dhawan (NRAO), Rob Fender (U Southampton), Sebastian Heinz (U Wisconsin-Madison), Elmar Koerding (U Nijmegen), Hans Krimm (NASA GSFC), Dipankar Maitra (U Michigan), Sera Markoff (U Amsterdam), Simone Migliari (ESA Madrid), Michael Rupen (NRAO), Dave Russell (U Amsterdam), Valeriu Tudose (ASTRON), Craig Sarazin (U Virginia)

3. Open questions in compact object physics Accretion/ejection coupling Jet launching mechanism Feedback effect on surroundings Formation of black holes "Observations with X-ray telescopes provide a complementary probe [to gravitational radiation] of the nature of space-time near the event horizon at the edge of a black hole... Yet another probe of black holes is the jets that are frequently created by massive spinning black holes in active galactic nuclei... It is proposed to combine the results from many types of telescopes operating simultaneously to understand how jets are made and how they shine. This will then lead to a better understanding of how gravity operates around a black hole. " – Astro2010 (p75)

4. What does the VLBA provide? High angular resolution High sensitivity Homogeneous array Dedicated VLBI array that can do ToOs any time

5. JACPOT aims BH, NS, WD outbursts: –Compare jet formation across the three source classes Depth of gravitational potential well Stellar surface Stellar magnetic field

6. Disc-jet coupling across the stellar mass scale

7. JACPOT aims BH, NS, WD outbursts: –Compare jet formation across the three source classes Depth of gravitational potential well Stellar surface Stellar magnetic field –First tests of the current paradigm for BH systems –Determine whether compact jets exist in WD/NS systems Time-resolved, high-angular resolution monitoring Multi-wavelength coverage

8. Black holes: H1743-322

9. Neutron stars: Aquila X-1 No transient ejecta, no internal shocks Radio emission triggered at state transitions First milliarcsecond-scale detections Radio quenching in soft states Miller-Jones et al. (2010)

10. White dwarfs: SS Cygni Similar disc-jet coupling First milliarcsecond-scale detections Marginal detection of resolved jets Astrometry: testing the Disc Instability Model

11. Important unanswered questions Universality of results –Control for varying black hole properties Spin? Magnetic field? Efficient vs inefficient accretion flows? Leptonic vs baryonic? –Is Aql X-1 representative of NS sources? –Are jets launched in white dwarfs? Derived physical parameters rely crucially on distance –Speeds –(Transition) luminosities

12. How to make progress Sample multiple sources of each class Pursue astrometric campaigns Push deeper on NS, WD systems

13. Enabled by Dynamic scheduling –Allows ToOs Bandwidth upgrade –Better constraints on NS, WD –Probe reverse transition in BH –Fainter (=closer) calibrators Correlator upgrade –Multiple phase centers to find closer calibrators Single EVLA antenna –Extra short baselines Phased EVLA and HSA –Required for faintest sources

14. Core requirements The ability to conduct ToO observations any time Rapid response to time-critical observations Dense time sampling Short baselines for imaging scattered targets Long baselines for astrometric targets High sensitivity to probe faint systems

15. Progress with a reduced VLBA Focus only on highest-yield science –Hard -> Soft transition (brightest) –Astrometry Dynamic scheduling –Move away from fixed-schedule whenever possible –Recognition of different critical timescales –Shorter, fixed duration blocks with higher BW –Sharing (automated) geodetic blocks Reduced number of antennas –5 SW baselines critical for imaging Galactic sources Substitute an EVLA antenna for Galactic observations? –Longest baselines critical for astrometry Retain at least one of MK, SC