The mystery surrounding the whereabouts of a supermassive black hole has deepened.
Despite searching with NASA’s Chandra X-ray Observatory and Hubble Space Telescope, astronomers have no evidence that a distant black hole estimated to weigh between 3 billion and 100 billion times the mass of the Sun is anywhere to be found.
This missing black hole should be in the enormous galaxy in the center of the galaxy cluster Abell 2261, which is located about 2.7 billion light years from Earth. This composite image of Abell 2261 contains optical data from Hubble and the Subaru Telescope showing galaxies in the cluster and in the background, and Chandra X-ray data showing hot gas (colored pink) pervading the cluster. The middle of the image shows the large elliptical galaxy in the center of the cluster.
Nearly every large galaxy in the Universe contains a supermassive black hole in their center; with a mass that is millions or billions of times that of the Sun. Since the mass of a central black hole usually tracks with the mass of the galaxy itself, astronomers expect the galaxy in the center of Abell 2261 to contain a supermassive black hole that rivals the heft of some of the largest known black holes in the Universe.
Using Chandra data obtained in 1999 and 2004 astronomers had already searched the center of Abell 2261’s large central galaxy for signs of a supermassive black hole. They looked for material that has been superheated as it fell towards the black hole and produced X-rays, but did not detect such a source.