Black Hole up to 100 Billion Times Mass of Sun is Missing: This image from Abell 2261 contains x-ray data from Chandra (pink) showing hot gases invading the cluster as well as optical data from Hubble and the Subaru telescope which shows galaxies in the cluster and in the background.
Astronomers have used these telescopes to search the galaxy in the center of the image for a black hole, weighing between 3 and 100 billion times the Sun, which should be there. No sign of this black hole has been found, deepening a mystery about what is going on in this system. Radiography: NASA / CXC / Univ of Michigan / K. Gültekin; Optics: NASA / STScI and NAOJ / Subaru; Infrared: NSF / NOAO / KPNO; Radio: NSF / NOAO / VLA
Abell 2261 galaxy
You would think it would be difficult to lose one of the largest black holes in the universe. However, scientists are currently baffled by the apparent absence of the supermassive black hole at the center of the Abell 2261 galaxy cluster – a monster that weighs between 3 and 100 billion times the mass of the sun.
At the center of nearly every galaxy, including our own, is a supermassive black hole. These black holes usually scale to the size of the galaxy, so the larger the galaxy, the larger the black hole. Abell 2261, which is located 2.7 billion light years away, has a very large central galaxy and is therefore expected to have a similarly sized supermassive black hole. But strangely, astronomers have been unable to locate this particular black hole.
This ongoing puzzle has meant that Abell 2261 has been studied by various instruments over the years, including the Subaru Telescope, the Hubble Space Telescope, and the Chandra X-Ray Observatory. A previous study used Chandra’s data to find the x-rays produced by matter when it falls into the black hole and becomes overheated, but found no such evidence.
It’s really, really strange, and the latest study probed Chandra’s data even deeper. He looked for evidence that the black hole had somehow been ejected from its position in the center of the galaxy. While the study found no evidence for the black hole itself, it found some to suggest that a merger may have taken place.
A merger is a dramatic event when two galaxies merge and the central black holes of each galaxy also merge, throwing ripples called gravitational waves. If these waves were not distributed evenly in all directions, the black hole could have moved away from its place in the heart of the galaxy.
This suggestion, called a “receding black hole”, is only theoretical as such a thing has never been observed before. But if that’s true, it could provide an exciting new way for scientists to study gravitational waves.