The Event Horizon Telescope: exploring strong gravity and accretion physics

Abstract

The Event Horizon Telescope (EHT), a global sub-millimeter wavelength very long baseline interferometry array, is now resolving the innermost regions around the supermassive black holes Sgr A* and M87. Using black hole images from both simple geometric models and relativistic magnetohydrodynamical accretion flow simulations, we perform a variety of experiments to assess the promise of the EHT for studying strong gravity and accretion physics during the stages of its development. We find that (1) the addition of the LMT and ALMA along with upgraded instrumentation in the "Complete" stage of the EHT allow detection of the photon ring, a signature of Kerr strong gravity, for predicted values of its total flux; (2) the inclusion of coherently averaged closure phases in our analysis dramatically improves the precision of even the current array, allowing (3) significantly tighter constraints on plausible accretion models and (4) detections of structural variability at the levels predicted by the models. While observations at 345 GHz circumvent problems due to interstellar electron scattering in line-of-sight to the galactic center, short baselines provided by CARMA and/or the LMT could be required in order to constrain the overall shape of the accretion flow. Given the systematic uncertainties in the underlying models, using the full complement of two observing frequencies (230 and 345 GHz) and sources (Sgr A* and M87) may be critical for achieving transformative science with the EHT experiment.

17 pages, 7 figures, 10 tables. Accepted by MNRAS 10 October 2014

References in corpus (9)

• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• Jet Launching Structure Resolved Near the Supermassive Black Hole in M87
• Stability of Relativistic Jets from Rotating, Accreting Black Holes via Fully Three-Dimensional Magnetohydrodynamic Simulations
• Global General Relativistic MHD Simulation of a Tilted Black-Hole Accretion Disk
• The Submillimeter Bump in Sgr A* from Relativistic MHD Simulations
• Simulating the Emission and Outflows from Accretion Disks
• Imaging the Supermassive Black Hole Shadow and Jet Base of M87 with the Event Horizon Telescope
• Relative Astrometry of Compact Flaring Structures in Sgr A* with Polarimetric VLBI
• Greenland Telescope Project --- Direct Confirmation of Black Hole with Sub-millimeter VLBI

Cited by in corpus (12)

• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• Assessments of Ali, Dome A, and Summit Camp for Mm-wave Observations Using MERRA-2 Reanalysis
• Absorption of electromagnetic and gravitational waves by Kerr black holes: Shadows, superradiance and the spin-helicity effect
• Constraint on the black-hole spin of M87 from the accretion-jet model
• Superradiance in the sky
• An accretion-jet model for M87: interpreting the spectral energy distribution and Faraday rotation measure
• Relative depolarization of the black hole photon ring in GRMHD models of Sgr A* and M87*
• Bondi-Hoyle-Lyttleton accretion in the presence of small rigid bodies around a black hole
• Observable Emission Features of Black Hole GRMHD Jets on Event Horizon Scales
• Generalized no-hair theorems without horizons
• Orbits in a stochastic Schwarzschild geometry
• Wind accretion onto compact objects