Evaluation of New Submillimeter VLBI Sites for the Event Horizon Telescope

Abstract

The Event Horizon Telescope (EHT) is a very long baseline interferometer built to image supermassive black holes on event-horizon scales. In this paper, we investigate candidate sites for an expanded EHT array with improved imaging capabilities. We use historical meteorology and radiative transfer analysis to evaluate site performance. Most of the existing sites in the EHT array have median zenith opacity less than 0.2 at 230 GHz during the March/April observing season. Seven of the existing EHT sites have 345 GHz opacity less than 0.5 during observing months. Out of more than forty candidate new locations analyzed, approximately half have 230 GHz opacity comparable to the existing EHT sites, and at least seventeen of the candidate sites would be comparably good for 345 GHz observing. A group of new sites with favorable transmittance and geographic placement leads to greatly enhanced imaging and science on horizon scales.

References in corpus (9)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• 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
• Electron and proton heating in trans-relativistic magnetic reconnection
• Stochastic Optics: A Scattering Mitigation Framework for Radio Interferometric Imaging
• 3.5-Year Monitoring of 225 GHz Opacity at the Summit of Greenland

Cited by in corpus (52)

• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
• Key Science Goals for the Next-Generation Event Horizon Telescope
• Modelling the Sgr A* Black Hole Immersed in a Dark Matter Spike
• Testing Horndeski Gravity from EHT Observational Results for Rotating Black Holes
• Superradiant evolution of the shadow and photon ring of Sgr A${}^{\star }$
• EHT tests of the strong-field regime of General Relativity
• Reference Array and Design Consideration for the next-generation Event Horizon Telescope
• Toward determining the number of observable supermassive black hole shadows
• Stringent axion constraints with Event Horizon Telescope polarimetric measurements of M87${}^{\star }$
• Comparison of the ion-to-electron temperature ratio prescription: GRMHD simulations with electron thermodynamics
• Measuring Spin from Relative Photon Ring Sizes
• Black Hole Polarimetry I: A Signature of Electromagnetic Energy Extraction
• Photon Ring Astrometry for Superradiant Clouds
• Multi-frequency Black Hole Imaging for the Next-Generation Event Horizon Telescope
• Observational Signatures of Frame Dragging in Strong Gravity
• Selective Dynamical Imaging of Interferometric Data
• Constraining Wormhole Geometries using the Orbit of S2 Star and the Event Horizon Telescope
• The Galactic Center as a laboratory for theories of gravity and dark matter
• First Very Long Baseline Interferometry Detections at 870μm
• Black hole parameter estimation with synthetic Very Long Baseline Interferometry data from the ground and from space
• Using Machine Learning to Link Black Hole Accretion Flows with Spatially Resolved Polarimetric Observables
• Horizonless spacetimes as seen by present and next-generation Event Horizon Telescope arrays
• Birefringence Tomography for Axion Cloud
• Accretion Flow Morphology in Numerical Simulations of Black Holes from the ngEHT Model Library: The Impact of Radiation Physics
• Enabling Transformational ngEHT Science via the Inclusion of 86 GHz Capabilities
• Note on fundamental physics tests from black hole imaging: Comment on "Hunting for extra dimensions in the shadow of Sagittarius A${}^{\ast }$"
• alpha-Deep Probabilistic Inference (alpha-DPI): efficient uncertainty quantification from exoplanet astrometry to black hole feature extraction
• Analysis of Orbital Configurations for Millimetron Space Observatory
• Dynamic and polarimetric VLBI imaging with a multiscalar approach
• Probing Axions via Light Circular Polarization and Event Horizon Telescope
• Probing Plasma Physics with Spectral Index Maps of Accreting Black Holes on Event Horizon Scales
• Measuring the Ellipticity of M 87* Images
• Impacts of nonthermal emission on the images of a black hole shadow and extended jets in two-temperature GRMHD simulations
• Analyzing Deflection Angles and Photon Sphere Dynamics of Magnetically Charged Black Holes in Nonlinear Electrodynamic
• Swarm intelligence for full Stokes dynamic imaging reconstruction of interferometric data
• Probing neutrino production in blazars by millimeter VLBI
• Imaging the event horizon of M87* from space on different timescales
• Expanding Sgr A* dynamical imaging capabilities with an African extension to the Event Horizon Telescope
• Probing Accretion Turbulence in the Galactic Center with EHT Polarimetry
• Prospects of using closure traces directly for imaging in Very Long Baseline Interferometry
• Impact of the nonthermal electron radiation effects on the horizon scale image structure of Sagittarius A*
• A comparative analysis of GNSS-inferred precipitable water vapour at the potential sites for the Africa Millimetre Telescope
• Multi-frequency VLBI Observations of the M 84 Inner Jet/Counterjet
• Effect of Earth's Oblateness on Black Hole Imaging Through Earth-Space and Space-Space VLBI
• Analysis of the accuracy of GNSS inferred precipitable water vapour against that from a 210 GHz WVR at the H.E.S.S. site
• Extreme magnetic fields around black holes
• The case for an all-sky millimetre survey at sub-arcminute resolution
• Multiobjective optimization for scattering mitigation and scattering screen reconstruction in VLBI observations of the Galactic Center
• Photon Ring Symmetries in Simulated Linear Polarization Images of Messier 87*
• Cross-correlations between mm-wave line-intensity mapping and weak lensing surveys: preliminary consideration of long-term prospects
• DoG-HiT: A novel VLBI Multiscale Imaging Approach