BBC Sky at Night Magazine
Quasars turn off their galaxies
The winds of black holes can be so strong they stop stars forming
A recent examination of Hubble observations has found that some quasars are so energetic they ‘turn off’ their galaxies, stopping them from producing stars.
Quasars are supermassive black holes which have matter raining down onto them. This creates huge amounts of radiation, heating the surrounding gas and dust to enormous temperatures. If the heat is intense enough, the surrounding gas accelerates until it’s travelling a few per cent of the speed of light.
“The amount of mechanical
energy that these outflows carry is up to several hundred times higher than the luminosity of the entire Milky Way Galaxy,” says Nahum Arav from Virginia Tech, who led the study.
This wave of material slams into the galaxy’s dust lanes, stopping them from producing stars, providing a potential answer to the long-standing mystery of what shuts off stellar birth in massive galaxies. https://hubblesite.org