The transient and variable Universe is a growing field in modern astrophysics, and it is starting to focus major, multi-messenger observing efforts. Because of their small physical size, variability at the fastest time scales is associated with compact stellar remnants (black holes, neutron stars, and white dwarfs). These compact objects exhibit variations down to the sub-second regime, which are found to be tightly related to their relevant physical processes and emission mechanisms.
High-time resolution (sub-minute) observations of compact objects are providing remarkable insights into fundamental questions, such as how black hole accretion, jets and outflows operate; the physics of condensed matter (i.e. neutron stars and white dwarfs); and the interaction between highly relativistic plasmas and strong magnetic fields. A good example are coordinated X-ray/optical/radio observing programs, which are helping us to probe emission sites and mechanisms in an unprecedented way. Fast timing is also allowing us to resolve the dynamical time-scales of binaries harbouring two compact stars. These systems, whose fundamental parameters can be therefore inferred, are one of the most promising candidates to detect gravitational waves.
This special session is dedicated to multi-wavelength, high-time resolution studies of compact objects, with an emphasis on the more unexplored optical regime. It will bring together the X-ray and radio communities, where sub-second time scales have been accessible for decades, and the optical community, which is now beginning to successfully exploit fast readout cameras. The last part of the session will focus upon present and future timing observing facilities. This will cover a broader range of topics, such as those related to transients of unknown nature, stellar-phenomena and extra-solar planets.
- Timing stellar-mass Black Holes
- Timing compact stars
- Instrumentation and facilities: present and future