4 days ago
US-led scientists discover new evidence on origins of intermediate-mass black holes
Black holes are generally grouped into three sizes: stellar-mass black holes, which are about five to 50 times the mass of the sun; supermassive black holes, with millions to billions of times the sun's mass; and intermediate-mass black holes, which fall somewhere in between.
Four new studies have brought fresh insight into the mystery of intermediate-mass black holes. The research was led by Assistant Professor Karan Jani, founding director of the Vanderbilt Lunar Labs Initiative, with funding from the National Science Foundation and Vanderbilt University.
The main study, titled "Properties of 'Lite' Intermediate-Mass Black Hole Candidates in LIGO-Virgo's Third Observing Run," was published in Astrophysical Journal Letters, with the team reexamining data from the LIGO detectors in the U.S. and the Virgo detector in Italy.
They found that the detected gravitational waves came from mergers of black holes weighing between 100 and 300 times the mass of the sun, marking the largest black hole collisions ever recorded.
According to Jani, black holes are like cosmic fossils that hold clues to the early universe. The newly identified group of black holes, revealed in this analysis, provides a unique opportunity to learn more about the very first stars that formed after the Big Bang.
Earth-based detectors like LIGO can only catch a brief moment of the final collision of these 'lighter' intermediate-mass black holes, making it hard to understand how they form. To learn more, Jani's lab is focusing on the upcoming LISA mission—a space-based project by the European Space Agency and NASA set to launch in the late 2030s.
Two additional studies published in the Astrophysical Journal demonstrated that the upcoming LISA mission can track intermediate-mass black holes years before they merge, providing new insights into their origins, evolution, and fate. The research also highlighted how detecting gravitational waves requires extreme precision—comparable to hearing a pin drop during a hurricane.
The researchers noted that this work supports the idea that intermediate-mass black holes are among the most important sources for gravitational-wave detectors, both on Earth and in space. Each new detection helps scientists better understand where these black holes come from and why they exist within this unusual mass range.
Looking ahead, the team plans to investigate how detectors on the moon could help observe intermediate-mass black holes in the future. Access to lower gravitational-wave frequencies from the lunar surface could help identify the environments where these black holes exist—something that Earth-based detectors cannot achieve.
The scientist pointed out that this is an exciting time, not only for studying black holes but also for combining scientific research with the new era of space and lunar exploration. It presents a rare chance to train the next generation of students whose discoveries will be influenced by, and conducted from, the moon, Jani added.
