Congrats to SXS member Elias Most (Asst. Prof. at @caltech.edu) on being named one of the 126 Sloan Research Fellows for 2026! www.caltech.edu/about/news/t...
17.02.2026 19:10
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Congrats to SXS member Elias Most (Asst. Prof. at @caltech.edu) on being named one of the 126 Sloan Research Fellows for 2026! www.caltech.edu/about/news/t...
Two of our papers on black-hole scattering have been published in Physical Review D! 🎉
To celebrate, here is a visualisation of the gravitational wave emission from a close scattering encounter: youtu.be/u9wBZEYfyAM
Paper 1: doi.org/10.1103/p6fx...
Paper 2: doi.org/10.1103/bdsb...
Our latest paper explores what happens when we push numerical relativity to the extreme when simulating black-hole scattering with the Spectral Einstein Code (SpEC). Check out this thread by the lead author to find out more!
Oh and I forgot to share to the feeds... please share!
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🎉 Happy paper publication day! 🎉 Our third catalog of binary black hole simulations, now published in Classical and Quantum Gravity. And it's open access!
Scheel et al. 2025 Class. Quantum Grav. 42 195017
iopscience.iop.org/article/10.1...
Also on the @arxiv.bsky.social at arxiv.org/abs/2505.13378
Rapidly spinning Kerr black hole in a dynamically evolved moving puncture gauge. Shown in color are the gravitational energy density and toroidal magnetic field in the meridional plane. Streamlines indicate the static component of the gravitational electric field and magnetic fields. The black ellipse marks the black hole horizon; white dashed contours denote the ergosphere.
Just published in Physical Review Letters! Check out this article by SXS researchers Boyeneni, Wu and Most (@caltech.edu) on interpreting colliding black holes similar to the attraction of two electric charges.
🔒 journals.aps.org/prl/abstract...
🔓 arxiv.org/abs/2504.15978
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Volume rendering of a circumbinary magnetically arrested accretion disk simulation in a non-erupting state, when the cooling is treated with an adiabatic prescription.
Cranking up the temperature! SXS researchers Hai-Yang Wang, Elias Most and Philip Hopkins (@caltech.edu) show how hot flows around supermassive black hole binaries with strong magnetic fields alter their feeding behavior. Full results at arxiv.org/abs/2508.16855
Fluctuations in the toroidal component of the magnetic field (top) and electric field (bottom) in the simulated magnetar quake event.
Earthquakes on neutron stars?! SXS researchers Louis Burnaz and Elias Most (@caltech.edu) and Ashley Bransgrove (Princeton) simulate how these could be detected in signals from very active radio burst transients. Read their results at arxiv.org/abs/2508.18033
A spacetime waltz. Simulations from @sxs-collaboration.bsky.social consistent with our 86 most confident new detections, each showing the orbiting components and their emitted gravitational waves
www.youtube.com/watch?v=3B6W...
🎬I Markin/T Dietrich/H Pfeiffer
#GWTC4 🔭🧪⚛️☄️🐚
🎉 Great news 🎉 — yesterday CQG accepted our third catalog paper!! The accepted manuscript can be found on their site here: iopscience.iop.org/article/10.1...
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2025 ICTP Dirac Medal Goes to Gravity Explorers
2025 ICTP Dirac Medal Goes to Gravity Explorers: The award is attributed to four scientists who have turned black holes into windows onto the deepest laws of nature www.ictp.it/news/2025/8/...
We now have our first paper on binary black hole scattering simulations generated with the Spectral Einstein Code (SpEC)! For more info on modelling these high-energy systems, see this thread by the lead author!
Check out this article about star quakes and monster shocks — research done by SXS collaboration members Yoonsoo Kim and Elias Most, both at @caltech.edu
I’m incredibly proud to be part of this and to have my simulations turn into the first publicly available scattering and dynamical capture waveforms!
Below is a plot I made for the Einstein Toolkit Blue Book (arXiv:2503.12263) showing the waveforms SXS:BBH:3999 (scatter) and SXS:BBH:4000 (capture).
Bonus: here's an animation I generated showing how the sausage was made. Each frame is one commit from the paper repo.
There’s a lot more work to do: higher mass ratios, higher eccentricity, and meeting the accuracy requirements of next-generation detectors. Stay tuned for the next version of our catalog! But for now, check out the latest catalog paper at arxiv.org/abs/2505.13378.
13/13
We make it publicly available so everyone has high-quality binary black hole simulation data at their fingertips for their research! Of course, we’re not done yet—
12/13
Six years is a long time, so there are too many details to summarize here. You can read about all of them in the new SXS catalog paper. We have already been doing a ton of science with this data (www.black-holes.org/for-research... for a list of paper using SpEC).
11/13
Because we generated so much data, we needed a new waveform format, which is typically 6 times more compressed than before. The new format is handled seamlessly by the sxs package, which also fetches and caches waveforms (and other data) as needed.
10/13
Out of the 2,018 simulations in the last catalog paper, we deprecated 282. We added 2,020 new non-deprecated simulations (and even uploaded another 112 new but deprecated simulations).
9/13
More recent simulations are more accurate than older ones, and some old simulations had issues that were only uncovered recently. Therefore we now deprecate simulations if we need (though the old data remains available, by passing an argument in the sxs package).
8/13
Over the years, we made many improvements to the Spectral Einstein Code (SpEC, www.black-holes.org/for-research...) that performed all these simulations (Sec. 3 discusses our methods and some of these improvements).
7/13
Figure 7 from our new paper, showing how well different angular harmonics converge.
Eight pages of the new paper are dedicated to studying the quality of our waveforms! For example, one of our plots shows how well different angular harmonics are converging (we provide all the way up to ℓ=8). Our median waveform difference between resolutions is 4*10^-4.
6/13
Our spectral methods continue to be highly efficient—over 1,000 times more efficient than finite-difference methods of comparable accuracy. We always provide multiple resolutions, so anyone can verify our numerical convergence.
5/13
The median simulation length is 22 orbits, while the longest is 148 orbits. Here’s a visual overview of the before and after of our parameter-space coverage:
4/13
Figure 1 from our new catalog paper. We accurately capture precession, memory, eccentricity, and high mass ratio systems. For full details, see the paper.
This data is freely available via data.black-holes.org and through the sxs package for python (installable via your favorite package manager, see sxs.rtfd.io for docs). Here’s a sampling of some more extreme systems in our catalog, showcasing a lot of the physics we can capture:
3/13
This catalog update comes six years after our last catalog (arxiv.org/abs/1904.04831), with too many improvements to list here. Our catalog now has 3,756 simulations, the largest and most accurate numerical relativity catalog to date.
2/13
Figure 1 from our new catalog paper. We accurately capture precession, memory, eccentricity, and high mass ratio systems. For full details, see the paper.
We are excited to release a major update to our catalog of binary black hole simulations, available at arxiv.org/abs/2505.13378! Such simulations are key to LIGO/Virgo/KAGRA being able to extract science from their gravitational wave detections.
1/13
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When simulating orbiting black holes, we move our grid with the holes! One of the key lessons of general relativity is coordinates are meaningless. We exploit this to choose comoving coordinates where the metric changes as little as possible.
www.youtube.com/watch?v=j4WG...
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