Abstract for Proposal 088073
Revealing the nature of ballistic jet ejections in M31 microquasars
Ballistic jets - launched as systems transit to the highest mass
accretion rates - are the most powerful kinetic events associated
with accretion. Studying how the inflow and jet couple is vital for
understanding the launching, yet is prohibited in Galactic sources due
to absorption of the X-ray bright accretion disc. By studying sources in
nearby galaxies we can avoid these issues as there are in principle many
such systems with far lower absorption columns. We propose a series of
observations of any new Eddington-rate black hole outburst discovered
in pre-approved Swift monitoring of M31. Together with pre-approved,
targeted radio observations, these will allow us to study the coupling
of inflow and outflow, and also determine the black hole spin to probe
its role in launching jets.
Details on Observing Strategy and Trigger Criteria
Swift will provide fortnightly snapshots to identify sources in the
central regions of M31 transitioning to ~10^39 erg/s. We have a pipeline
in place to automatically analyse and locate new sources. Once a new
source transiting to the required luminosity is located, we will start
monitoring with AMI-LA, trigger our Chandra pre-approved ToO and trigger
the XMM-Newton campaign. We request a rapid reaction time to the initial
trigger of less than a week (the observations themselves to be taken
across a period of 2 weeks). Once the decline from outburst has been
modelled (again, using Swift), we will trigger the follow-up XMM-Newton
observations to start around the time the source dips below ~30% of
Eddington (~< 3x10^38 erg/s), catch the source in the decaying soft state
and constrain the spin. We expect to be able to provide advanced notice
of this occurring should the source obey typical e-folding decay times.