Enabling Transformational ngEHT Science via the Inclusion of 86 GHz Capabilities

Abstract

We present a case for significantly enhancing the utility and efficiency of the ngEHT by incorporating an additional 86 GHz observing band. In contrast to 230 or 345 GHz, weather conditions at the ngEHT sites are reliably good enough for 86 GHz to enable year-round observations. Multi-frequency imaging that incorporates 86 GHz observations would sufficiently augment the ($u,v$) coverage at 230 and 345 GHz to permit detection of the M87 jet structure without requiring EHT stations to join the array. The general calibration and sensitivity of the ngEHT would also be enhanced by leveraging frequency phase transfer techniques, whereby simultaneous observations at 86 GHz and higher-frequency bands have the potential to increase the effective coherence times from a few seconds to tens of minutes. When observation at the higher frequencies is not possible, there are opportunities for standalone 86 GHz science, such as studies of black hole jets and spectral lines. Finally, the addition of 86 GHz capabilities to the ngEHT would enable it to integrate into a community of other VLBI facilities $-$ such as the GMVA and ngVLA $-$ that are expected to operate at 86 GHz but not at the higher ngEHT observing frequencies.

arXiv comment23 pages, 10 figures

References in corpus (54)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• 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. V. Physical Origin of the Asymmetric Ring
• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole
• First M87 Event Horizon Telescope Results. VII. Polarization of the Ring
• First Sagittarius A* Event Horizon Telescope Results. III: Imaging of the Galactic Center Supermassive Black Hole
• First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multi-wavelength Observations, Data Processing, and Calibration
• First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
• High Resolution Linear Polarimetric Imaging for the Event Horizon Telescope
• Interferometric Imaging Directly with Closure Phases and Closure Amplitudes
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
• The limb-brightened jet of M87 down to 7 Schwarzschild radii scale
• High-Sensitivity 86GHz (3.5mm) VLBI Observations of M87: Deep Imaging of the Jet Base at a 10 Schwarzschild-Radius Resolution
• A Global 86GHz VLBI Survey of Compact Radio Sources
• Two-temperature, Magnetically Arrested Disc simulations of the jet from the supermassive black hole in M87
• A Feature Movie of SiO Emission 20-100 AU from the Massive Young Stellar Object Orion Source I
• The Size, Shape, and Scattering of Sagittarius A* at 86 GHz: First VLBI with ALMA
• Evaluation of New Submillimeter VLBI Sites for the Event Horizon Telescope
• Extreme Jet Ejections from the Black Hole X-ray Binary V404 Cygni
• High Precision Astrometric Millimeter VLBI Using a New Method for Atmospheric Calibration
• Jet collimation in NGC 315 and other nearby AGN
• Discovery of Substructure in the Scatter-Broadened Image of Sgr A*
• Metrics and Motivations for Earth-Space VLBI: Time-Resolving Sgr A* with the Event Horizon Telescope
• Jet outflow and gamma-ray emission correlations in S5 0716+714
• Studying Black Holes on Horizon Scales with VLBI Ground Arrays
• Spatially resolved origin of mm-wave linear polarization in the nuclear region of 3C 84
• Connection between inner jet kinematics and broadband flux variability in the BL Lac object S5 0716+714
• The Power of Simultaneous Multi-Frequency Observations for mm-VLBI: Astrometry up to 130 GHz with the KVN
• VLBI observations of weak sources using fast frequency switching
• Multi-frequency Black Hole Imaging for the Next-Generation Event Horizon Telescope
• Verification of the Astrometric Performance of the Korean VLBI Network, using comparative SFPR studies with the VLBA at 14/7 mm
• The magnetic field structure in CTA 102 from high resolution mm-VLBI observations during the flaring state in 2016-2017
• Global millimeter VLBI array survey of ultracompact extragalactic radio sources at 86 GHz
• Pinpointing the jet apex of 3C 84
• Astrometrically Registered Simultaneous Observations of the 22 GHz H${}_2$O and the 43GHz SiO masers towards R Leonis Minoris using KVN and Source/Frequency Phase Referencing
• Interferometric Monitoring of Gamma-ray Bright Active Galactic Nuclei II: Frequency Phase Transfer
• The Transformational Power of Frequency Phase Transfer Methods for ngEHT
• Persistent Non-Gaussian Structure in the Image of Sagittarius A* at 86 GHz
• VLBA imaging of the 3mm SiO maser emission in the disk-wind from the massive protostellar system Orion Source I
• The jet collimation profile at high resolution in BL Lacertae
• The Power of Simultaneous Multi-frequency Observations for mm-VLBI: Beyond Frequency Phase Transfer
• Localizing the $\gamma$-ray emitting region in the blazar TXS 2013+370
• Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron IV. The quasar 3C 345 at 18 cm: Magnetic field structure and brightness temperature
• A Model for Anisotropic Interstellar Scattering and its Application to Sgr A*
• The Science Case for Simultaneous mm-Wavelength Receivers in Radio Astronomy
• Sub-milliarcsecond imaging of a bright flare and ejection event in the extragalactic jet 3C 111
• CMB from the South Pole: Past, Present, and Future
• VLBA Scientific Memorandum n. 31: Astrometric calibration of mm-VLBI using "Source/Frequency Phase Referenced" observations

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• Key Science Goals for the Next-Generation Event Horizon Telescope
• The Black Hole Explorer: Motivation and Vision
• Reference Array and Design Consideration for the next-generation Event Horizon Telescope
• Multi-frequency Black Hole Imaging for the Next-Generation Event Horizon Telescope
• The Transformational Power of Frequency Phase Transfer Methods for ngEHT
• Measuring Black Hole Light Echoes with Very Long Baseline Interferometry
• Shared-optical-path VLBI frequency phase transfer from 86 to 258 GHz on an 8600 km baseline: Demonstrated with the APEX and IRAM 30 m telescopes