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Phil Lynch

@physlynch.bsky.social

Irish gravitational physicist at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Germany modelling gravitational waves from black hole binaries for the upcoming LISA mission

67 Posts701 Follower374 Folgt
Phil Lynch@physlynch.bsky.social · 2mo ago

Happy to announce my work on applying NITs to the dynamics of eccentric comparable mass black hole binaries is finally on the arxiv! I've been working on this project since I started my postdoc so I am delighted to finally get this over the line! arxiv.org/abs/2606.30594

Efficient Eccentric Effective-One-Body Dynamics via Near-Identity Averaging Transformations

Next-generation gravitational-wave detectors, such as LISA, the Einstein Telescope, and Cosmic Explorer, will require accurate and efficient models of long-lived black-hole binary signals, including t...

arxiv.org

Astrobites@astrobites.bsky.social · 3mo ago

From @laurie-amen.bsky.social: Did you know that many observed black holes theoretically shouldn’t exist? Today’s paper gathers gravitational wave evidence for how these impossible black holes might have formed. ⚛️ 🔭 ☄️ 🧪 astrobites.org/2026/05/09/many-mergers-might-fill-mass-gap/

Many Mergers Might Fill the Mass Gap

Did you know that many observed black holes theoretically shouldn’t exist? Today’s paper gathers gravitational wave evidence for how these impossible black holes might have formed.

astrobites.org

Olly Long@hyperbolly.bsky.social · 9mo ago

How much information can we gain by pushing numerical relativity to its limit by simulating black hole scattering encounters? My latest paper (below) explores these extreme regions of the black-hole scattering parameter space using simulations generated using the Spectral Einstein Code (SpEC).

Black-hole scattering with numerical relativity: Self-force extraction and post-Minkowskian validation

The asymptotic nature of unbound binary-black-hole encounters provides a clean method for comparing different approaches for modeling the two-body problem in general relativity. In this work, we use n...

arxiv.org

Peter Coles 🏳️‍🌈 🏳️‍⚧️ 🇮🇪@telescoper.bsky.social · 11mo ago

A Decade of Gravitational Waves This is just a quick post to mark the fact that it is now ten years to the day since the first detection of gravitational waves by Advanced LIGO. The acronym LIGO stands for Laser Interferometer Gravitational-wave Observatory. It wasn't until February 11th 2016 that…

A Decade of Gravitational Waves

This is just a quick post to mark the fact that it is now ten years to the day since the first detection of gravitational waves by Advanced LIGO. The acronym LIGO stands for Laser Interferometer Gravitational-wave Observatory. It wasn't until February 11th 2016 that the result was announced at a press conference (which I blogged about here), but the signal itself arrived on 14th September 2015, exactly a decade ago; the name given to the event was GW150914.

telescoper.blog

Phil Lynch@physlynch.bsky.social · 11mo ago

New paper on the arXiv today about systematic errors when modelling the gravitation waveform from extreme mass ratio inspirals and their impact on LISA data science Huge thanks to my collaborators, especially Hassan Khalvati, for getting this project over the line! 🧪⚛️🔭🧮 arxiv.org/abs/2509.08875

A posting on the arXiv preprint server. Title: Systematic errors in fast relativistic waveforms for Extreme Mass Ratio Inspirals Authors: Hassan Khalvati, Philip Lynch, Ollie Burke, Lorenzo Speri, Maarten van de Meent, Zachary Nasipak Abstract: Accurate modeling of Extreme Mass-Ratio Inspirals (EMRIs) is essential for extracting reliable information from future space-based gravitational wave observatories. Fast waveform generation frameworks adopt an offline/online architecture, where expensive relativistic computations (e.g. self-force and black hole perturbation theory) are performed offline, and waveforms are generated rapidly online via interpolation across a multidimensional parameter space. In this work, we investigate potential sources of error that result in systematic bias in these relativistic waveform models, focusing on radiation-reaction fluxes. Two key sources of systematics are identified: (i) the intrinsic inaccuracy of the flux data, for which we focus on the truncation of the multipolar mode sum, and (ii) interpolation errors from transitioning to the online stage. We quantify the impact of mode-sum truncation and analyze interpolation errors by using various grid structures and interpolation schemes. For circular orbits in Kerr spacetime with spins larger than a≥0.9, we find that ℓmax≥30 is required for the necessary accuracy. We also develop an efficient Chebyshev interpolation scheme, achieving the desired accuracy level with significantly fewer grid points compared to spline-based methods. For circular orbits in Kerr spacetimes, we demonstrate via Bayesian studies that interpolating the flux to a maximum global relative error that is equal to the small mass ratio is sufficient for parameter estimation purposes. For 4-year long quasi-circular EMRI signals with SNRs=O(100) and mass-ratios 10^−4−10^−6, a global relative error of 10−6 yields mismatches <10^−3 and negligible parameter estimation biases.
Olly Long@hyperbolly.bsky.social · last yr.

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).

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SXS Collaboration@sxs-collaboration.bsky.social · last yr.

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 🧪⚛️🔭

Figure 1 from our new catalog paper. We accurately capture precession, memory, eccentricity, and high mass ratio systems. For full details, see the paper.
LISA Community@lisacommunity.bsky.social · last yr.

Welcome to the #LECSTalks! series, where we showcase the people, activity, and science taking place around the LISA Early Career Scientists community. 🎤 Today we feature Ben Leather, postdoctoral researcher at the MPI for Grav Physics, talking about Waveform Modelling with Gravitational Self-Force.

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astrafoxen@astrafoxen.bsky.social · last yr.

I spent almost 2 hours painstakingly copying the orbits of all 128 Saturnian moons from the announcement MPEC and reformatting them for visualization... Behold, here are the orbits of ALL 128 MOONS OF SATURN. This isn't just a moon system—it's a literal asteroid belt around Saturn! 🧪🔭☄️

Saturn's outer moon system viewed from the north pole of Saturn. Moons orbiting in clockwise (retrograde) orbits have red-colored orbits while moons orbiting counterclockwise (prograde; in the direction of Saturn's spin) are colored blue. With so many irregular moons occupying the same region and intersecting each other, the irregular moon system looks like a donut-shaped vortex surrounding Saturn. Each of the 128 new moons is highlighted in the diagram with a white point representing their location, and a brighter-colored orbit. Previously-known moons of Saturn are included in the diagram, but are colored darker. The regular moons of Saturn are colored turquoise and the outermost regular moons (Titan, Hyperion, and Iapetus) labeled with their name. At the lower left corner are scale indicators to help visualize the scale of Saturn's irregular moon system. A small gray circle at the left left corner is shown to represent the diameter of the Earth-Moon orbital distance. A linear scale bar is labeled "10 million km" (6.2 million mi) to give a standard distance.View of Saturn's irregular moon system, tilted at an angle to show the toroidal belt-like shape of the system. Each moon is labeled with their names in turquioise. Red orbits = retrograde direction, and blue orbits = prograde direction. Turquoise curves closer to the center are orbits of Saturn's regular moons.Side view of Saturn's irregular moon system, tilted at an angle to show the toroidal belt-like shape of the system. Red orbits = retrograde direction, and blue orbits = prograde direction. Turquoise curves closer to the center are orbits of Saturn's regular moons. The irregular moons of Neptune (dark green) are also visible in the background to the right of Saturn. The horizontal red line protruding right of Saturn is the orbit path of Saturn.
Jake Postiglione@jakepost.tech · 2y ago

Ever wonder how gravitational wave detectors like LISA would hear the signal of binary black holes orbiting around a supermassive black hole? 🔭 Well check out my first 1st author paper investigating that very topic, live on the arXiv today! 🔥📄 arxiv.org/abs/2502.10591 Explainer in 🧵👇 1/10

Evolution of LISA Observables for Binary Black Holes Lensed by an SMBH

Binary black holes (BBH) are expected to form and merge in active galactic nuclei (AGN), deep in the potential well of a supermassive black hole (SMBH), from populations that exist in a nuclear star c...

arxiv.org

Saavik ‘Careful of the Ankle’ Ford@saavikford.bsky.social · 2y ago

Ok doomscrollers, here is a HAPPY news story from Gizmodo about LISA, the gravitational wave observatory that will be launched by ESA, with NASA support, in the mid-2030s (I’m quoted, as are @jakepost.tech & Emanuele Berti). 🧪🔭⚛️

LISA: What the Revolutionary Gravitational Wave Observatory Will Actually See

LISA is set to revolutionize our understanding of the gravitational universe and the interactions that make the entire cosmos turn.

gizmodo.com

Emily Hunt@emily.space · 2y ago

A very fascinating paper went up on the arXiv today! Jesse Han & El-Badry et al. reanalysed the 21 known 'hypervelocity' stars in the #milkyway. They find strong evidence that the LMC (Large Milky/Magellanic Cloud) has a supermassive black hole at its core! 🤯 arxiv.org/abs/2502.00102

A figure from the paper (Figure 4). It shows the locations of known hypervelocity stars as black circles, with the predicted overdensity that the LMC would cause shown in red. Full caption: Predicted on-sky overdensity of hypervelocity stars originating from a 6 × 105M⊙ supermassive black hole in the LMC. The black open circles denote the Galactic coordinates of hypervelocity stars detected in the HVS Survey, while the grey-shaded regions mark areas excluded from the survey. The current position of the LMC is illustrated with a representative image, and its orbital trajectory is drawn with a red arrow. The forward model incorporating an SMBH in the LMC along with the selection effects of the HVS Survey predicts a prominent overdensity of HVS in the region enclosed by the red contours. The overdensity arises because stars are boosted in the direction of the LMC’s orbit. This model accurately reproduces the observed overdensity location, supporting the hypothesis of an SMBH in the LMC as a source of these stars.
Markus Pössel@mpoessel.de · 2y ago

When things go well, preparing for a lecture is one of my happy places. I get to read, and understand better, stuff that I'm interested in. I get to make diagrams and animations, always fun. Here is an animation of the motion of a star in a disk galaxy for your viewing pleasure: 1/ 🧪🔭

Nihar Gupte@nihar-gupte.bsky.social · 2y ago

Woke up this morning to see the sad news of the Palisades and Eaton fires. I hope everyone, their families, and pets are ok. I can't imagine what kind of anxiety it is wondering if your home is ok or not :( Here's some info on the fires based on a project I was working on in 2019. 1/11

Black Hole Perturbation Toolkit@bhptoolkit.bsky.social · 2y ago

First arXiv paper of 2025 that cites the BHPToolkit: "Post-adiabatic waveform-generation framework for asymmetric precessing binaries", Josh Mathews, Adam Pound, arxiv.org/abs/2501.01413

Post-adiabatic waveform-generation framework for asymmetric precessing binaries

Recent years have seen rapid progress in calculations of gravitational waveforms from asymmetric compact binaries containing spinning secondaries. Here we outline a complete waveform-generation scheme...

arxiv.org

Rhiannon Silva@rhiannonsilva.bsky.social · 2y ago

Happy birthday to “the most brilliant PhD thesis ever written in astronomy”! Cecilia Payne-Gaposchkin completed her thesis on January 1st, 1925*. She found that stars are composed mainly of hydrogen and helium, counter to the idea of the time, that the Sun and Earth were made of similar materials.

Title page from the thesis: HARVARD OBSERVATORY MONOGRAPHS HARLOW SHAPLEY, EDITOR No. 1 STELLAR ATMOSPHERES A CONTRIBUTION TO THE OBSERVATIONAL STUDY OF HIGH TEMPERATURE IN THE REVERSING LAYERS OF STARS BY CECILIA H. PAYNE PUBLISHED BỶ THE OBSERVATORY CAMBRIDGE, MASSACHUSETTS 1925 John G. Wolbach Library, Harvard-Smithsonian Center for AstrophysicsA black and white photo of Cecilia Payne-Gaposchkin. Credit: Smithsonian Institution.