2026 Simons Collaboration on Black Holes and Strong Gravity Annual Meeting

Vitor Cardoso
Niels Bohr Institute

Listening to Black Holes

One of the most remarkable possibilities of general relativity concerns gravitational collapse to black holes. Is the strong field dynamical regime of gravity well described by general relativity? In this talk, Vitor Cardoso will summarize the status of black hole spectroscopy and attempts at probing near horizon physics.
 

Katy Clough
Queen Mary University of London

New Physics in the Strong Field Regime

Katy Clough’s recent numerical work has shown the importance of including non-linear effects that modify the gravitational sector in the strong field regime in beyond GR theories, with PN predictions becoming unreliable over the late inspiral-merger phase. Combining the expertise of the collaboration in mathematically well posed formulations, numerics, and data analysis, Clough can now extend her studies to a representative subset of theories, and stress-test current diagnostic and modelling tools with fully consistent waveforms.
 

Neil Cornish
Montana State University

Observing Strong Gravity Phenomena: Dissecting Signals and Separating Interesting Effects From Noise

Theory predicts many interesting strong gravity effects both within and beyond general relativity. As the sensitivity of the detectors improves, it becomes possible to take apart gravitational wave signals and search for strong gravity phenomena such as spin precession, kicks, diffraction, and hereditary effects such as tails and memory. Our goal is to take signals apart and isolate these contributions to the signals, and also, to search for new effects that go beyond the predictions on general relativity. But we have to be sure that what appear to be interesting new effects are not just noise artifacts, due to non-Gaussian or non-stationary instrument noise. Neil Cornish will describe some of the newly developing techniques to dissect gravitational wave signals and go beyond the simplistic noise models that have been used in most previous analyses.
 

Jonathan Gair
Albert Einstein Institute

Connections in the Crowd: Challenges in Identifying Strong Gravity Features Across Populations

As gravitational wave detectors improve in sensitivity, not only will individual sources be observed with ever increasing signal-to-noise ratio, but the total population of observed systems will continuously increase. Multiple observations can in principle be combined hierarchically to find effects that are too weak to be detected at the individual event level, but this procedure is both computationally expensive and impacted by modelling assumptions. Challenges to overcome include modelling the between-source variability efficiently and accurately, performing model-agnostic hierarchical analyses, and building robustness to model misspecification and variability in the detector performance across the population. In this talk, Jonathan Gair will outline some of the computational and conceptual challenges and how they might be addressed over the next few years.
 

Daniel Holz
University of Chicago

Black Holes as Precision Strong Gravity Laboratories

GW150914 ushered in the era of observational strong gravity. That event revolutionized our understanding, representing a leap of many orders of magnitude. With a catalog of hundreds of sources, we are entering a qualitatively new regime of tests of general relativity. GW150914 had SNR=24, which was statistically unusually high for a first event. As the catalog of events grows, it inevitably leads to higher SNR events: the current catalog has 218 confirmed events supplemented by nearly 200 additional candidate signals, and the loudest event is now GW250114 with an SNR=80, allowing for percent-level tests of gravitational waveforms. Furthermore, larger catalogs naturally lead to a broader exploration of parameter space, including a wider range of spins, masses, and mass ratios, each of which provides novel arenas for strong-field tests. In this talk, Daniel Holz will discuss current and future probes of general relativity in its most extreme exemplars.
 

Gary Horowitz
University of California, Santa Barbara

Update on Extremal and Near-Extremal Black Holes

In this talk, Gary Horowitz will discuss some recent developments concerning extremal and near-extremal black holes. These include instabilities of extremal black holes and the breakdown of effective field theory close to near-extremal black holes.
 

Alex Lupsasca
Vanderbilt University

Black Hole Photon Rings and Gravitational Ringdown

Gravitational-wave observations probe the ringdown of a newly formed black hole, as it relaxes to equilibrium through the emission of quasinormal modes. Meanwhile, efforts to image black holes are beginning to target the photon ring, produced by light that executes multiple orbits before escaping to a distant observer. In this talk, Alex Lupsasca will review recent progress in the study of these two phenomena and explain their deep theoretical connection in the eikonal limit.
 

Nicolás Yunes
University of Illinois Urbana-Champaign

The Simons Collaboration on Black Holes and Strong Gravity: Vision and Opportunities

Black holes provide our clearest laboratory for studying gravity in its most nonlinear and dynamical regime. With rapid progress in mathematical relativity, numerical simulation, data analysis, and gravitational-wave astronomy, we are now in a position to ask sharper questions about what happens when gravity is pushed to its limits and how those answers can be extracted from data. The Simons Collaboration on Black Holes and Strong Gravity was created to bring these threads together. Its central aim is to unite theory, computation, and observation in order to understand strong gravity in Einstein’s theory, explore well-motivated extensions beyond it, and develop robust methods to search for new signatures in gravitational-wave observations. In this opening talk, I will outline the scientific vision of the collaboration, the structure of its main research directions, and the opportunities that lie ahead at the interface of black-hole physics, strong-field gravity, and data-driven discovery. Nicolás Yunes will also discuss the broader goal of building a shared intellectual framework and community that can help shape the future of strong-gravity science.

Participation in the meeting falls into the following four categories. An individual’s participation category is communicated via their letter of invitation.

The Simons Foundation will never ask for credit card information or require payment for registration to our events.

Group A – PIs, Speakers & Organizers

Individuals in Group A receive travel and hotel coordination within the following parameters:

Travel
Economy Class: For flights that are three hours or less to your destination, the maximum allowable class of service is Economy class.
Premium Economy Class: For flights where the total air travel time (excluding connection time) is more than three hours and less than seven hours per segment to your destination, the maximum allowable class of service is premium economy.
Business Class: When traveling internationally (or to Hawaii/Alaska) travelers are permitted to travel in Business Class on those segments that are seven hours or more. If the routing is over budget, a premium economy or mixed-class ticket will be booked.

Hotel
Up to 3 nights at the conference hotel, arriving on Wednesday, May 6, 2026 and departing on Saturday, May 9, 2026.

Group B – Funded Participants

Individuals in Group B receive travel and hotel coordination within the following parameters:

Travel
Economy class travel will be booked regardless of flight length.

Hotel
Up to 3 nights at the conference hotel, arriving on Wednesday, May 6, 2026 and departing on Saturday, May 9, 2026.

Group C – Unfunded Participants
Individuals in Group C will not receive financial support but are encouraged to enjoy all conference-hosted meals.

Group D – Remote Participants
Individuals in Group D will participate in the meeting remotely

Air & Rail
For funded individuals, the foundation will arrange and pay for round-trip travel from their home city to the conference city. All travel and hotel arrangements must be booked through the Simons Foundation’s preferred travel agency.

Travel Deviations

The following travel specifications are considered deviations and will only be accommodated if the cost is less than or equal to the amount the Simons Foundation would pay for a standard round-trip ticket from your home city to the conference city:

• Preferred airline
• Preferred travel class
• Specific flights/flight times
• Travel dates outside those associated with the conference
• Arriving or departing from an airport other than your home city or conference city airports, i.e. multi-segment or triangle trips.

All deviations must be reviewed and approved by the Simons Foundation and, if the cost is more than what would normally be paid, a reimbursement quote must be obtained through the foundation’s travel agency before proceeding to booking and paying for travel out of pocket. All reimbursements for travel booked directly will be paid after the conclusion of the meeting.

Changes After Ticketing

All costs related to changes made to ticketed travel are to be paid for by the participant and are not reimbursable. Please contact the foundation’s travel agency for further assistance.

Personal & Rental Cars
Personal car and rental trips over 250 miles each way require prior approval from the Simons Foundation via email.

Rental cars must be pre-approved by the Simons Foundation.

The Hotel AKA NoMad offers valet parking. Please note there are no in-and-out privileges when using the hotel’s garage, therefore it is encouraged that participants walk or take public transportation to the Simons Foundation.

Hotel
Funded individuals who require hotel accommodations are hosted by the foundation for a maximum of 3 nights at the conference hotel, arriving on Wednesday, May 6, 2026 and departing on Saturday, May 9, 2026.

Any additional nights are at the attendee’s own expense. To arrange accommodations, please register at the link included in your invitation.

Hotel AKA NoMad
131 Madison Avenue

New York, NY 10016
https://www.stayaka.com/hotel-aka-nomad

Overview:
In-person participants will be reimbursed for meals and local expenses including ground transportation. Expenses should be submitted through the foundation’s online expense reimbursement platform after the meeting’s conclusion.

Expenses accrued because of meetings not directly related to the Simons Foundation-hosted meeting (a satellite meeting or meeting held at another institution, for example) will not be reimbursed by the Simons Foundation and should be paid by other sources.

Below are key reimbursement takeaways; a full policy will be provided with the final logistics email circulated approximately 2 weeks prior to the meeting’s start.

Meals:
The daily meal limit is $125; itemized receipts are required for expenses over $24 USD. The foundation DOES NOT provide a meal per diem and only reimburses actual meal expenses up the following amounts.

• Breakfast $20
• Lunch $30
• Dinner $75

Allowable Meal Expenses

• Meals taken on travel days (when you traveled by air or train).
• Meals not provided on a meeting day, dinner on Friday for example.
• Group dinners consisting of fellow meeting participants paid by a single person will be reimbursed up to $75 per person and the amount will count towards the $125 daily meal limit.

Unallowable Expenses

• Meals taken outside those provided by the foundation (breakfast, lunch, breaks and/or dinner).
• Meals taken on days not associated with Simons Foundation-coordinated events.
• Minibar expenses.
• Meal expenses for a non-foundation guest.
• Ubers, Lyfts, taxis, etc., taken to and from restaurants in Manhattan.
  • Accommodations will be made for those with mobility restrictions.

Ground Transportation:
Expenses for ground transportation will be reimbursed for travel days (i.e. traveling to/from the airport or train station) as well as subway and bus fares while in Manhattan are reimbursable.

Transportation to/from satellite meetings are not reimbursable.

Attendance

In-person participants and speakers are expected to attend all meeting days. Participants receiving hotel and travel support wishing to arrive on meeting days which conclude at 2:00 PM will be asked to attend remotely.

Entry & Building Access

Upon arrival, guests will be required to show their photo ID to enter the Simons Foundation and Flatiron Institute buildings. After checking-in at the meeting reception desk, guests will be able to show their meeting name badge to re-enter the building. If you forget your name badge, you will need to provide your photo ID.

The Simons Foundation and Flatiron Institute buildings are not considered “open campuses” and meeting participants will only have access to the spaces in which the meeting will take place. All other areas are off limits without prior approval.

If you require a private space to conduct a phone call or remote meeting, please contact your meeting manager at least 48-hours ahead of time so that they may book a space for you within the foundation’s room reservation system.

Guests & Children
Meeting participants are required to give 24-hour advance notice of any guests meeting them at the Simons Foundation either before or after the meeting. Outside guests are discouraged from joining meeting activities, including meals.

With the exception of Simons Foundation and Flatiron Institute staff, ad hoc meeting participants who did not receive a meeting invitation directly from the Simons Foundation are not permitted.

Children under the age of 18 are not permitted to attend meetings at the Simons Foundation. Furthermore, the Simons Foundation does not provide childcare facilities or support of any kind. Special accommodations will be made for nursing parents.

Meeting & Policy Questions
Christina Darras
Event Manager
[email protected]

Travel & Hotel Support
FCM Travel Meetings & Events
[email protected]
Hours: M-F, 8:30 AM-5:00 PM ET
+1-888-789-6639