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Next Steps for the Next Generation Event Horizon Telescope


The Science at the Horizons conference was comprised of at least 94 presentations and discussion sections, with over 500 participants from over 30 countries. Throughout this vibrant week of collaboration, we identified and refined fundamental ngEHT science goals, paving the way forward towards the next generation of EHT science. These goals include:

  • Cosmological assembly of most massive black holes (probably mergers)

  • Gravity ladder calibration: both spins and masses

  • Resolving final parsec binaries, if they exist

  • Measuring spin and spacetime tomography

  • New fundamental fields, such as ultralight fields and axions

  • Finding direct evidence of energy extraction from a black hole

  • Identifying important physics at the meso and micro scales, and adding new physics to simulations

  • Undersanding AGN variability with “fast” XRBs, empirical test of spin/BZ relation

  • High precision geodesy

  • Megamaser cosmology: spectral line observatory

  • GRB Follow-up

Moving forward, we plan to further refine the primary science drivers and observing requirements for the ngEHT. This will involve regular topical group meetings, shared ngEHT resources, a well-circulated ngEHT reference design, white papers for the ngEHT Science Book, and future ngEHT plenary meetings.


For those who would like to continue to engage with the ngEHT Science at the Horizons Conference:

Thank you to all the participants, speakers, and organizers who attended this meeting. We hope you feel as excited for the future of ngEHT science as we do. 

Next Steps for the Next Generation Event Horizon Telescope


The Science at the Horizons conference photo.

Credit: Nick Conroy


The Science at the Horizons conference mosaic.

Credit: Joseph Farah and BlackRainbow.

Conference Rationale and Summary

February 22-26, 2021

Please register to attend this meeting at

Questions? Contact the local organizing committee (LOC) at

Slack Link: (invitation required)

Rationale: Release of the first black hole image on 10 April 2019 has highlighted new possibilities of using event horizon scale precision measurements to address fundamental questions in astronomy and physics. EHT results have already constrained exotic black hole alternatives, determined the mass and spin orientation of the M87 black hole, and revealed the black hole shadow predicted by General Relativity, with more results expected with continued observations. Through the addition of new telescopes and higher observing frequencies, a next-generation EHT (ngEHT) can be engineered with substantially improved imaging capabilities to achieve a broad range of transformative science goals related to black hole accretion, jet physics, and strong-field GR.  


This ngEHT science meeting will bring together experts in black hole astrophysics and VLBI technology.  We will discuss the driving science goals, and the algorithmic and technical developments that are required to achieve them. The ngEHT will require a global collaborative effort, so there will be opportunities to discuss coordination of international efforts with the aim of assembling a new instrument capable of visionary science within this decade.  


This will be an online-only and open meeting with participation welcomed by experts from across the scientific community.


Conference topics will include:

  • Testing accretion modes and models for Sgr A* and M87.

  • Testing how black holes power relativistic jets.

  • Studies of flares with the ngEHT.

  • Tests of the Kerr metric: resolving the photon ring.

  • Beyond Sgr A* and M87: Expanded source populations with the ngEHT.

  • Multi-messenger science with the ngEHT.

  • Scientific opportunities with a space-enhanced array. 

  • Next-generation simulations of black hole accretion flows.

  • Next-generation algorithms for interferometric imaging.

  • Prospects for higher-frequency VLBI and multi-frequency observations.

  • ngEHT concept, architecture, and optimization.

LOC:  Lindy Blackburn, Nick Conroy (co-Chair), Mina Himwich, Britt Jeter (co-Chair), Tiffany Nichols, Daniel Palumbo, Alex Raymond, Paul Tiede.


SOC: Geoff Bower, Avery Broderick (co-Chair), Alessandra Buonanno, Vitor Cardoso, Shep Doeleman, Charles Gammie, Daryl Haggard, David Hughes, Michael Johnson (co-Chair), Chung-Pei Ma, Ramesh Narayan, Ue-Li Pen, Andy Strominger,  Anton Zensus.

Conference Highlights

Confirmed Speakers Include:

  • Asimina Arvanitaki, Perimeter Institute for Theoretical Physics

  • Alex Lupsasca, Princeton University

  • Alex Tetarenko, East Asian Observatory

  • Enrico Barausse, International School for Advanced Studies (SISSA)

  • Sarah Burke-Spolaor, West Virginia University

  • Eliot Quataert, Princeton University & University of California, Berkeley

  • Frank Eisenhauer, Max Planck Institute for Extraterrestrial Physics

  • George Wong, University of Illinois at Urbana-Champaign

  • Huan Yang, University of Guelph & Perimeter Institute for Theoretical Physics

  • Paolo Pani, Sapienza University of Rome

  • Jean-Pierre Luminet, French National Centre for Scientific Research

  • Rob Fender, University of Oxford

  • Matt Lister, Purdue University

  • Sera Markoff, University of Amsterdam

  • Silke Britzen, Max Planck Institute for Radio Astronomy

  • Alberto Sesana, University of Milano-Bicocca

  • Sasha Tchekhovskoy, Northwestern University

  • Sasha Philippov, Flatiron Institute

  • Jonelle Walsh, Texas A&M University

  • Andrew Chael, Princeton University

  • Neil Nagar, University of Concepción

  • Roger Blandford, Stanford University


Conference Schedule

You can find the block schedule below. The full schedule can be downloaded here.


Support for the ngEHT includes grants from the National Science Foundation, John Templeton Foundation, and the Gordon and Betty Moore Foundation.

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