English: This artist impression shows ultra-fast winds blasting out from the centre of galaxy Markarian 817. These winds, moving at many millions of kilometres per hour, clear out interstellar gas from a vast region of space. Without this gas, the galaxy can’t form new stars and the black hole in the galactic centre has little left to eat.
The inset shows what is happening at galaxy’s heart. A supermassive black hole draws in gas from its surroundings, which forms a hot, brightly lit ‘accretion disc’ (orange). The cause of the winds (white) is magnetic fields within the disc, which fling particles out in all directions at incredibly high speeds. These winds effectively block out X-rays (blue) which are sent out by the extremely hot plasma surrounding the black hole, called the corona.
Researchers caught Markarian 817 blasting out ultra-fast winds using ESA’s X-ray telescope XMM-Newton. Lasting for around a year, the winds will have significantly affected star formation in the galaxy. The fact that the black hole at the centre of the galaxy was showing rather average activity levels before producing the winds suggests that ultra-fast black hole winds are much more common than previously thought. In other words, black holes and their host galaxies strongly affect each other’s evolution.
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Separate images: large view of the galaxy and close-up of the centre
[Image description: Side view of a galaxy with spiral arms of bright blue stars separated by dark bands of interstellar dust. The galaxy’s active centre is blasting out a strong wind of gas in all directions, shown as yellowish-white streaks. An inset zooms in on the centre, showing that the wind is coming from a swirling disc of gas, lit up in orange and yellow, which encircles a supermassive black hole.]