Event Horizon Telescope
Project Summary:
A long standing goal in astrophysics is to directly observe the
immediate environment of a putative black hole with angular resolution
comparable to the event horizon. Realizing this goal would open a new
window on the study of General Relativity in the strong field regime,
accretion and outflow processes at the edge of a black hole, the
existence of an event horizon, and fundamental black hole physics.
Steady long-term progress on improving the capability of Very Long
Baseline Interferometry (VLBI) at short wavelengths has now made it
extremely likely that this goal will be achieved within the next decade.
The most compelling evidence for this is the recent observation by 1.3mm
VLBI of Schwarzschild radius scale structure in SgrA*, the compact
source of radio, submm, NIR and xrays at the center of the Milky Way.
SgrA* is thought to mark the position of a ~4 million solar mass black
hole, and because of its proximity and estimated mass presents the
largest apparent event horizon size of any black hole candidate in the
Universe. This new 1.3mm VLBI detection confirms that short wavelength
VLBI of SgrA* can and will be used to directly probe the Event Horizon
of this black hole candidate: in short, SgrA* is the right object, VLBI
is the right technique, and this decade is the right time. Over the
next decade, our group proposes to combine existing and planned mm/submm
facilities into a high sensitivity, high angular resolution "Event
Horizon Telescope" that will bring us as close to the edge of black hole
as we will ever come. This effort will include development and
deployment of submm dual polarization receivers, highly stable frequency
standards to enable VLBI at 230-450GHz, higher bandwidth VLBI backends
and recorders, as well as commissioning of new submm VLBI sites. We
emphasize that while there is development and procurement involved, the
path forward is clear and the recent successful observations have
removed much of the risk that would normally be associated with such an
ambitious project.
MIT Haystack Observatory
Arizona Radio Observatory - University of Arizona
Harvard-Smithsonian Center for Astrophysics
UC Berkeley Radio Astronomy Laboratory
Joint Astronomy Centre - James Clerk Maxwell Telescope
Caltech Submillimeter Observatory
Combined Array for Research in Millimeter-wave Astronomy
Max Planck Institut fuer Radioastronomie
National Astronomical Observatory of Japan
Institut de Radio Astronomie Millimetrique
National Radio Astronomy Observatory
Academia Sinica Institute for Astronomy and Astrophysics
Large Millimeter Telescope
617.715.5400 
