First M87 Event Horizon Telescope Results. II. Array and Instrumentation

Abstract

The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth. At a nominal operating wavelength of ~1.3 mm, EHT angular resolution (lambda/D) is ~25 micro-as, which is sufficient to resolve nearby supermassive black hole candidates on spatial and temporal scales that correspond to their event horizons. With this capability, the EHT scientific goals are to probe general relativistic effects in the strong-field regime and to study accretion and relativistic jet formation near the black hole boundary. In this Letter we describe the system design of the EHT, detail the technology and instrumentation that enable observations, and provide measures of its performance. Meeting the EHT science objectives has required several key developments that have facilitated the robust extension of the VLBI technique to EHT observing wavelengths and the production of instrumentation that can be deployed on a heterogeneous array of existing telescopes and facilities. To meet sensitivity requirements, high-bandwidth digital systems were developed that process data at rates of 64 gigabit/s, exceeding those of currently operating cm-wavelength VLBI arrays by more than an order of magnitude. Associated improvements include the development of phasing systems at array facilities, new receiver installation at several sites, and the deployment of hydrogen maser frequency standards to ensure coherent data capture across the array. These efforts led to the coordination and execution of the first Global EHT observations in 2017 April, and to event-horizon-scale imaging of the supermassive black hole candidate in M87.

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Cited by in corpus (176)

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• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• Black Hole Shadows, Photon Rings, and Lensing Rings
• First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole
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• Influence of Accretion Flow and Magnetic Charge on the Observed Shadows and Rings of the Hayward Black Hole
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• The Photon Ring in M87*
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• The Image of the M87 Black Hole Reconstructed with PRIMO
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• Spectral and Imaging properties of Sgr A* from High-Resolution 3D GRMHD Simulations with Radiative Cooling
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• The Transformational Power of Frequency Phase Transfer Methods for ngEHT
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• Signatures of the accelerating black holes with a cosmological constant from the ${\text{Sgr A}}^{\star }$ and ${\text{M87}}^{\star }$ shadow prospects
• Enabling Transformational ngEHT Science via the Inclusion of 86 GHz Capabilities
• A quantum-corrected approach to black hole radiation via a tunneling process
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• 4D Einstein-Gauss-Bonnet gravity: Massless particles and absorption of planar spin-0 waves
• MeqSilhouette v2: Spectrally-resolved polarimetric synthetic data generation for the Event Horizon Telescope
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• Photon Emission Near Myers-Perry Black Holes in the Large Dimension Limit
• Shadow behavior of an EMSG charged black hole
• Orbital configurations of spaceborne interferometers for studying photon rings of supermassive black holes
• A Review of Contemporary Atomic Frequency Standards
• The Next Generation Event Horizon Telescope Collaboration: History, Philosophy, and Culture
• Optical appearance of numerical black hole solutions in higher derivative gravity
• Quasi-harmonic oscillations of charged particles in static axially symmetric space-times immersed in a uniform magnetic field
• Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes
• Spins of supermassive black holes M87* and SgrA* revealed from the size of dark spots in Event Horizon Telescope Images
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• Compact objects in quadratic Palatini gravity generated by a free scalar field
• Black Hole Shadow Observations with Space-Ground Interferometers
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• Expanding Sgr A* dynamical imaging capabilities with an African extension to the Event Horizon Telescope
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• The Effects of Resolution on Black Hole Accretion Simulations of Jets
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• Not all spacetime coordinates for general-relativistic ray tracing are created equal
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• Shadow and near-horizon characteristics of the acoustic charged black hole in curved spacetime
• Millimeter-wave Monitoring of Active Galactic Nuclei with the Africa Millimetre Telescope
• Sirius: A Prototype Astronomical Intensity Interferometer Using Avalanche Photodiodes in Linear Mode
• $COD:$ An Algorithm for Shape Reconstruction of Transiting Celestial Bodies through Topological Optimization
• Noncommutative information is revealed from the static detector outside the black hole
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• Implementing Remote Observing at the JCMT
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• Polish Doughnuts around Scalarized Kerr Black Holes
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