Powerful winds from an ultra-luminous X-ray binary

Artist’s impression depicting a compact object – either a black hole or a neutron star – feeding on gas from a companion star in a binary system.

Since gas cannot fall in from all directions in a rotating system, it forms a swirling disc around the compact object. This causes matter to heat up and emit light at many wavelengths, especially X-rays. However, not all the gas in the disc is swallowed, and some of it is blown away in the form of winds or jets.

Scientists using ESA's XMM-Newton have discovered gas streaming away at a quarter of the speed of light from two very bright X-ray binaries, known as ultra-luminous X-ray sources, that are located in nearby galaxies. The discovery confirms that these sources conceal a compact object accreting matter at extraordinarily high rates.