Observations of “Jellyfish galaxies” with ESO’s Very Large Telescope have revealed a previously unknown way to fuel supermassive black holes. It seems the mechanism that produces the tentacles of gas and newborn stars that give these galaxies their nickname also makes it possible for the gas to reach the central regions of the galaxies, feeding the black hole that lurks in each of them and causing it to shine brilliantly.
An international team of astronomers has discovered glowing gas clouds surrounding distant quasars. The new survey of these active galaxies indicates that haloes around quasars are far more common than expected. The properties of the haloes in this surprising find are also in striking disagreement with currently accepted theories of galaxy formation in the early universe.
Astronomers have used NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton X-ray observatory to discover an extremely luminous, variable X-ray source located outside the centre of its parent galaxy. This peculiar object could be a wandering black hole that came from a small galaxy falling into a larger one.
When a star passes within a certain distance of a black hole, the stellar material gets stretched and compressed as the black hole swallows it, briefly releasing an enormous amount of energy as a flare. Astronomers have now observed infrared light echoes from these “stellar tidal disruption” events reflected by dust encircling a black hole.
Quasars are supermassive black holes that sit at the centre of enormous galaxies, accreting matter. They shine so brightly that they are among the most distant objects in the universe that we can currently study. New work from a team led by Carnegie’s Eduardo Bañados has discovered 63 new quasars from when the universe was just 7 percent of its present age.
Supermassive black holes do not give off any of their own light, hence the word “black” in their name. However, many black holes pull in surrounding material and emit powerful bursts of X-rays. Collectively, these active black holes can be thought of a cosmic choir, singing in the language of X-rays. Their “song” is what astronomers call the cosmic X-ray background.