Despite careful searches with the Hubble and Chandra space telescopes, astronomers have been unable to find a presumed supermassive black hole at the heart of a giant galaxy.
By measuring subtle changes in the timing of millisecond pulsar flashes, researchers are close to confirming the presence of a background “sea” of gravity waves.
Black holes merging in the accretion disc of a supermassive black hole like the one at the core of the Milky Way might generate a visible signature, astronomers say.
Astronomers have found an “ultra-stripped supernova” that created a second neutron star in a tight binary system, matching theoretical predictions for how such binaries are formed in otherwise disruptive blasts.