NASA’s Chandra X-ray Observatory, along with other telescopes, has discovered a supermassive black hole that has shredded a star and is now using the remnants to strike another star or smaller black hole. This finding bridges two cosmic enigmas and sheds light on the environments surrounding the largest black holes.
An artist’s illustration depicts a disk of material, created when the supermassive black hole (on the right) tore apart a star with its intense tidal forces. Over several years, this disk expanded and intersected with another object—either a star or a small black hole—orbiting the giant black hole. Each collision generates bursts of X-rays, detected by Chandra. The inset includes Chandra’s data (in purple) alongside an optical image from Pan-STARRS (in red, green, and blue).
In 2019, an optical telescope in California observed a burst of light, later classified as a “tidal disruption event” (TDE), where a black hole tears apart a star that strays too close. This event was named AT2019qiz.
Simultaneously, scientists were tracking “quasi-periodic eruptions” (QPEs), brief and regular bursts of X-rays near supermassive black holes. The new study suggests a link between TDEs and QPEs, proposing that QPEs are generated when objects collide with the disk created by TDEs.
In 2023, astronomers used both Chandra and Hubble to analyze the debris after the tidal disruption event concluded. Chandra’s observations, taken over 14 hours, revealed a weak signal in the first and last segments but a strong signal in the middle, highlighting the dynamic nature of these cosmic phenomena.
Researchers utilized NASA’s Neutron Star Interior Composition Explorer (NICER) to monitor AT2019qiz for repeated X-ray bursts, revealing that it erupts approximately every 48 hours. This finding was confirmed with data from NASA’s Neil Gehrels Swift Observatory and India’s AstroSat telescope.
Additionally, ultraviolet data from Hubble, collected alongside Chandra’s observations, allowed scientists to measure the size of the disk surrounding the supermassive black hole. They discovered that if any object orbits the black hole in about a week or less, it would inevitably collide with the disk, triggering eruptions.
These findings have significant implications for the search for more quasi-periodic eruptions linked to tidal disruptions. Identifying additional instances would enable astronomers to assess the prevalence and distances of objects in close orbits around supermassive black holes, many of which could serve as excellent targets for future gravitational wave observatories.
The study detailing these results was published in the October 9, 2024, issue of *Nature*, with Matt Nicholl from Queen’s University Belfast as the first author. The complete list of authors is available in the paper, accessible online at https://arxiv.org/abs/2409.02181.
NASA’s Marshall Space Flight Center manages the Chandra program, with science operations controlled by the Smithsonian Astrophysical Observatory’s Chandra X-ray Center in Cambridge, Massachusetts, and flight operations in Burlington, Massachusetts.
