LIGO finds one dark-matter candidate

MIT and European researchers said on May 12 that they had developed a way to use gravitational-wave data to look for possible signs of dark matter around merging black holes. The team applied the method to public signals from the LIGO-Virgo-KAGRA network and said one event, GW190728, stood out as a tentative candidate. The authors said the result was not a detection of dark matter and described the finding as a screening result that would need follow-up. The study appeared in Physical Review Letters on May 12. ### Which gravitational-wave event drew the researchers’ attention? GW190728 was the one event in the screen that showed possible signs of a dark-matter imprint, according to MIT News and the paper’s abstract. The researchers said they reviewed 28 of the clearest signals from the first three LIGO-Virgo-KAGRA observing runs and found that 27 were consistent with black holes merging in vacuum. The paper also named GW190814 alongside GW190728 as an event for which vacuum lay outside the 95% credible region in the authors’ analysis. (news.mit.edu) But the abstract said GW190728 was the case that showed tentative evidence once the team included what it called superradiance priors. ### What exactly are the authors claiming — and not claiming? The authors said they had not detected dark matter. MIT News said the method is intended as a way to screen gravitational-wave catalogs for hints that can then be checked with other techniques. (news.mit.edu) Josu Aurrekoetxea, a postdoctoral researcher in MIT’s physics department and a co-author, said dark matter “has to be dense enough for us to see its effects.” He said black holes could provide a mechanism to enhance that density, making gravitational-wave signals a place to search for it. (arxiv.org) ### How would dark matter show up in a black-hole merger signal? The paper said light scalar particles are a plausible dark-matter candidate and that dense scalar configurations around black holes could alter the binary’s dynamics during inspiral. (news.mit.edu) Those changes would then leave signatures in the gravitational-wave waveform measured on Earth, according to the authors. The model in the paper was built for binaries in scalar environments rather than empty space. (news.mit.edu) The abstract said the team validated the waveform model against numerical relativity simulations before applying it in a Bayesian analysis of the LIGO-Virgo-KAGRA catalog. ### Who did the work, and what data did they use? Soumen Roy of Université Catholique de Louvain led the study with Rodrigo Vicente of the University of Amsterdam, Josu Aurrekoetxea of MIT, Katy Clough of Queen Mary University of London and Pedro Ferreira of Oxford University, according to MIT News and the paper. (arxiv.org) The researchers used publicly available LIGO-Virgo-KAGRA catalog data from the network’s first three observing runs. LIGO-Virgo-KAGRA is the global network that detects gravitational waves from black hole mergers and other astrophysical sources. The collaboration’s publications page shows the group has continued releasing new analyses from later observing runs, including multiple papers posted in March 2026 from the fourth run. ### Why does GW190728 remain tentative? The paper’s abstract said GW190728 showed tentative evidence for a scalar environment with a Bayes factor of about 3.5 when superradiance priors were included. (news.mit.edu) The same abstract said the result was consistent with a light scalar of mass around 10^-12 electron volts. MIT News said the method offers upper limits on scalar densities around most compact binaries and one possible lead for follow-up, rather than a confirmed signal. (news.mit.edu) The next step, based on the paper and MIT’s account, is to test similar signatures in additional LIGO-Virgo-KAGRA events as more catalog data become available. (arxiv.org)