A composite image, combining data from the Hubble Space Telescope, the Subaru Telescope and the Chandra X-ray Observatory, shows galaxy cluster Abell 2261 and the hot gas (shown in pink) that pervades the cluster. The presumed supermassive black hole at the heart of the cluster’s central galaxy has eluded detection, raising the possibility it was ejected in a gravitational recoil event. Image: X-ray: NASA/CXC/Univ of Michigan/K. Gültekin; Optical: NASA/STScI and NAOJ/Subaru; Infrared: NSF/NOAO/KPNO
Astronomers have been searching for a 10 billion solar-mass black hole at the heart of a truly massive galaxy for the past decade.
They still haven’t found it.
The galaxy in question, A2261-BCG, is the most massive member of the remote Abell 2261 galaxy cluster some 2.7 billion light years away in the constellation Hercules. It is gargantuan by almost any standard, spanning about 10 times the width of the Milky Way. Its core alone measures about 10,000 light years across, the largest yet seen.
All large galaxies are thought to harbour a supermassive black hole. The mass of the black hole generally scales with the mass of the host galaxy, meaning A2261-BCG should be home to a black hole with 3 billion to 10 billion times ...