New catalog of LIGO-Virgo-KAGRA observations published
The latest catalog, GWTC-4, includes 128 new candidates from the fourth observing run, more than doubling the previous total.
Researchers at the Max Planck Institute for Gravitational Physics and at Leibniz University Hannover make significant contributions to doubling the number of gravitational-wave detections, presented in a forthcoming special issue of Astrophysical Journal Letters.
When the densest objects in the universe collide and merge, the violence sets off ripples, in the form of gravitational waves, that reverberate across space and time, over hundreds of millions and even billions of years. By the time they pass through Earth, such cosmic ripples are barely discernible.
And yet, scientists are able to detect them, thanks to a global network of gravitational-wave observatories: the U.S.-based National Science Foundation Laser Interferometer Gravitational-Wave Observatory (NSF LIGO), the Virgo interferometer in Italy, and the Kamioka Gravitational Wave Detector (KAGRA) in Japan. Together, the observatories “listen” for faint wobbles in the gravitational field that could have come from far-off astrophysical smash-ups.
The latest update of the LVK gravitational-wave catalog
Now the LIGO-Virgo-KAGRA (LVK) Collaboration is publishing its latest compilation of gravitational-wave detections, presented in a forthcoming special issue of Astrophysical Journal Letters.
The LVK’s Gravitational-Wave Transient Catalog-4.0 (GWTC-4) comprises detections of gravitational waves from a portion of the observatories’ fourth and most recent observing run, which occurred between May 2023 and January 2024. During this nine-month period, the observatories detected 128 new gravitational-wave “candidates,” meaning that the signals are likely from extreme, far-off astrophysical sources. (The LVK detected about 300 mergers so far in the fourth run, but not all of these appear yet in the LVK catalog).
This newest crop more than doubles the size of the gravitational-wave catalog, which previously contained 90 candidates compiled from all three previous observing runs.
Read more
The Max Planck Institute for Gravitational Physics contributed to this success
Scientists at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, AEI) and at Leibniz University Hannover, including many PhD students and postdoctoral researchers, have contributed to this achievement:
- AEI researchers have developed sophisticated waveform models that are used to distinguish real cosmic sources from random fluctuations and terrestrial disturbances that appear in the detector.
- The waveform models used as templates to detect binary black holes and neutron-star—black-hole binaries were developed at the AEI. These state-of-the-art waveform models, augmented with spin-precession effects, are also employed for production runs on the signal candidates to infer their astrophysical and cosmological information.
- Another waveform model, developed at the AEI, includes the effect of mode asymmetry and the resulting “kick”, and is used in the analysis.
- Scientists at AEI have used signal candidates to search for deviations from general relativity.
- Neural network-based parameter estimation methods developed at the AEI provide a rapid and accurate way to infer the properties of binary black hole mergers.
- Researchers at the AEI provided the high-power pre-stabilized laser system for Advanced LIGO, and have developed and tested upgrades to the main laser source currently being used in the LIGO instruments.
- The amplifier stage of the current laser sources in the Virgo and KAGRA instruments is based on developments and tests carried out by a collaboration between the AEI in Hannover and the Laser Zentrum Hannover.
