Gravity Exploration Institute

This art, depicting the most massive merger detected to date, was created by our GEI PhD student, Sama Al-Shammari:

A 2025 news round-up from one of our GEI PhD students:

Infographic about GW241011 and GW241110 GW241011's source contained black holes about 13 and 8 times the mass of our Sun. The spin of the bigger black hole is high and bear aligned with the orbit. GW241110's source contained black holes about 17 and 8 times the mass of our Sun. The spin of the larger black hole is high and near anti-aligned with the orbit. Credit: Shanika Galaudage/Northwestern University/Adler Planetarium

We are pleased to announce our discovery of #GW241011 and #GW241110

Both come from binary black holes where one black hole is much larger than the other. The larger black holes have large spin. Could these black holes have formed in a previous merger?

ligo.org/science-summ...

#O4IsHere 🔭🧪⚛️☄️

YouTube video by University of Glasgow University of Glasgow celebrates 10th anniversary of first gravitational wave detection

A new mini-documentary by our colleagues at @uofgravity.bsky.social celebrating the 10th anniversary of our first detection and the progress in #GravitationalWave astronomy

youtu.be/SqhFtkQ4f2c

#GW10Years 🔭🧪⚛️🎢

Front cover of issue 27 of the LIGO Magazine 10 years of graviational wave astronomy GW150914 to GW231123: a signal that changed to world (p 6) GW231123: the most massive black hole merger yet! (p 24) GWTC-4.0 cataglgue paper (p 20) GW observatories of the future (p 34) Climate change conversations: Fossil-free supercomputing (p 40)

The latest issue of @ligomagazine.bsky.social is out now and free to read

🎉 Celebrate 10 years of gravitational-wave astronomy with us 🎉

ligo.org/wp-content/u...

🔭🧪⚛️ #GW10Years

A decade of discovery: Academics celebrate 10 years since the first detection of gravitational waves amid announcement of exciting new breakthrough Scientists celebrate anniversary and tests of Stephen Hawking's black hole area theorem

Today we celebrate the 10th anniversary of the first detection of gravitational waves by @ligo.org 🎉 Research by members of the Gravity Exploration Institute in Cardiff helped lay the foundation for that detection, which opened an exciting new window to the universe. Read more about it here:

“Black holes this massive are forbidden through standard stellar evolution models. One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes.”

From the article: “This is the most massive black hole binary we’ve observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation,” says Professor Mark Hannam, from Cardiff University and a member of the LIGO Scientific Collaboration.

Read more about the new announcement, including a quote from the Gravity Exploration Institute's @markdhannam.bsky.social here:
ligo.org/ligo-virgo-k...

GW231123: an unearthly signal A report on some actual science

My summary of the latest @ligo.org observation paper.

Massive black holes!

open.substack.com/pub/fictiona...

Several members from Cardiff's Gravity Exploration Institute will be taking part in this special gravitational wave science ceilidh (traditional Scottish dance) in Glasgow this week!

Prof Stephen Fairhurst of the Gravity Exploration Institute in Cardiff is the new spokesperson for the LIGO Scientific Collaboration! He is the first person from a non-US institution to hold this position. We are very pleased and proud that his many years of work within the LSC have been recognised.

🎉 We have reached 200 #GravitationalWave candidates in O4! 🎉

The fourth observing run (O4) of our detector network has had the best performance so far, with more candidates than ever before! We are currently busy analysing all these wonderful data and look forward to sharing results

#O4IsHere 🔭☄️

YouTube video by sciencejedi LIGO -- Dave Reitze We have Detected Gravitational Waves

Nine years ago we announced to the world that we have detected #GravitationalWaves we did it!

youtu.be/lslUF9gdYI8

You can read the paper here: journals.aps.org/prd/abstract...

Or the preprint version here: arxiv.org/abs/2009.14611

Compared to other unmodelled transient searches currently used for the LIGO and Virgo detectors, MLy is not only much faster, it also uses only a fraction of the computing power, making it extremely efficient.

...those from core-collapse supernovae, gamma ray bursts, or unknown sources.

Our new pipeline, MLy (pronounced “Emily”) will be able to detect such unmodelled signals within seconds, which is important for quickly triggering follow up searches in electromagnetic radiation and energetic particles.

Although CNNs have previously been used for analysing gravitational waves from sources with modelled signals, such as binary black holes and neutron stars, this is the first time the method has been usefully applied for the real-time detection of unmodelled signals in LIGO-Virgo data, such as...

Screenshot of the paper: "Toward real-time detection of unmodeled gravitational wave transients using convolutional neural networks" By Vasileios Skliris, Michael R. K. Norman, and Patrick J. Sutton. Physical Review D 110, 104034 – Published 15 November, 2024.

5 types of gravitational wave signals which were injected into real LIGO-Virgo detector data in order to test the efficiency of the detection algorithm: a high frequency white noise burst (WNB), binary black hole merger (BBH), core-collapse supernova (CCSN), circularly polarized sine-Gaussian (CSG), and a cosmic string cusp (CUSP).

A recent paper from the GEI presents the first convolutional neural network (CNN) analysis pipeline for the detection of generic transient gravitational waves signals, with sensitivity across a wide range of signal parameters, used for real-time searches in data from the LIGO and Virgo detectors.

Bangalore Sathyaprakash

Living Reviews in Relativity welcomes B. S. Sathyaprakash! Expert from Penn State University and Cardiff University joins as new Associate Editor for Gravitational Waves:
link.springer.com/journal/4111... #LivingRevRelativ #MeetTheEditors

Happy New Year! Blwyddyn Newydd Dda!

The people who attended those workshops helped shape the field of gravitational physics over the next 50 years and many are still active today.

... physicists and mathematicians could discuss relativity and gravitation. Experts came from around the world to discuss that year's topic, to present their recent work, to learn more about what others were doing in their field, and to spend time together, strengthening their scientific community.

A group of mathematicians and physicists standing in front of an old building. Their clothes identify the time as the 1970s.

The first Gregynog Relativity Workshop was held at Gregynog Hall in Mid Wales, September 1-3, 1975. The topic was Thermodynamic Properties of Gravitational Fields.

#flashbackfriday

When Bernard Schutz @bschutz.bsky.social moved to Cardiff in 1974, he began to organize workshops where...

Abhinav Patra, Lorenzo Aiello, Aldo Ejlli, William L. Griffiths, Alasdair L. James, Nikitha Kuntimaddi, Ohkyung Kwon, Eyal Schwartz, Henning Vahlbruch, Sander M. Vermeulen, Katherine L....
Direct Limits on Stochastic Length Fluctuations at Radio Frequencies
https://arxiv.org/abs/2410.09175

Direct Limits on Stochastic Length Fluctuations at Radio Frequencies The Quantum-Enhanced Space-Time (QUEST) experiment consists of a pair of co-located Power Recycled Michelson Interferometers, each designed to have a broadband, shot-noise limited displacement sensiti...

And for anyone interested in more technical details, here is a recent preprint of a paper about the experiment, with its first results.

QUEST for answers to mysteries of universe underway in new Cardiff lab Wolfson and HEFCW funded facility home to unique instruments for gravitational physics research

You can read more about the QUEST experiment here, with photos of the empty lab in May, just before we began building the experiment.

QUEST is already the most sensitive table-top system of its kind, and ongoing improvements will allow us to probe further, for a wide variety of station­ary signals like signatures of quantised space-time, scalar field dark matter candidates, and stochastic and continuous gravitational waves.

Bird's-eye view of a part of the experiment. There are two cylinders on a table, with pipes/tubes coming out the side of them, and there are many wires around. At the bottom of the photo are the pink crocs of the scientist taking the photo.

A physics laboratory with a lot of instruments on a table and vertical wires hanging everywhere. The instruments include cylinders and lasers.

Photos from our Quantum-Enhanced Space-Time (QUEST) experiment. This experiment searches for stochastic gravitational waves. The photos were taken by PhD student, Abhinav Patra, who has been working on QUEST in one of our laboratories at the Gravity Exploration Institute, Cardiff University.

A gravitational waves starter pack!