Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
Convened in the summer of 2013, the EHT Technical Working Group (ETWG) was tasked with:
1. Survey the capabilities at all EHT facilities
2. Establish a set of specifications for future EHT observations
3. Outline the technical developments needed to reach these goals
4. Based on prioritized science objectives, formulate a project roadmap that is grounded in technical feasibility with the resources available.
The supermassive black hole in the centre of the Milky Way, Sgr A*, is an ideal target for testing the properties of black holes. A number of experiments are being prepared or conducted, such as the monitoring of stellar orbits, the search for radio pulsars or the recording of an image of the shadow of a event horizon. The talk puts these efforts in context with other tests of general relativity and its alternatives.
In general relativity, astrophysical black holes are characterized uniquely in terms of their masses and spins and are described by the Kerr metric. The high sensitivity and resolution of the EHT will allow for unprecedented tests of the Kerr nature of black holes and, hence, of general relativity. I will present current and future limits on deviations from the Kerr metric from Sgr A* in the context of radiatively-inefficient accretion flow models.
I will discuss the prospects for finding additional radio pulsars in the Galactic center region and their utility for probing general relativity and other constituents in the region. This will include discussions of neutron star populations; radio wave scattering in and toward the Galactic center; issues and progress in discovering pulsars; and the precision to which discoverable pulsars can be timed
GRAVITY is a new instrument combining the four 8m ESO Very Large Telescopes in Chile. Other than the BlackHoleCam / EHT with its focus on imaging the shadow of the black hole against the surrounding accretion flow, the goal of GRAVITY is to measure dynamical processes in the immediate vicinity of the black hole, for example the motion of matter close to the last stable orbit and relativistic effects in stellar orbits.