M31_XMM-Newton

Astronomers have identified a micro-quasar in our neighbouring Andromeda galaxy, making it the first to be found outside the Milky Way.

The discovery should shed new light on how these objects shaped the first galaxies, billions of years ago.

Black holes

Quasars are ultra-luminous bodies, emitting x-rays at intensities strong enough to outshine an entire galaxy. They form when a black hole begins consuming a nearby star. As the star’s matter is pulled into orbit, it accelerates, giving it more energy. Eventually, the matter has so much energy that it begins emitting x-rays strong enough to be seen from Earth.

Despite this, they are still poorly understood: most are found at the heart of distant galaxies, too far away to be seen clearly. Those in our galaxy are micro-quasars – much smaller than their distant counterparts – and obscured by dust.

This quasar’s location, 2.5 million light years away, makes it ideal for further investigation: it is both near enough to study, and far enough to avoid being obscured by our galaxy.

Galaxy formation

By studying quasars in greater detail, the team of astronomers hopes to learn more about their most unusual feature: a pair of jets that propel matter at speeds close to the speed of light. These are thought to have played a role in distributing matter in the early universe, forming the clusters of gas and dust that eventually formed galaxies and stars.

Despite the quasar’s small size, Dr Matthew Middleton, who led the research, believes that any findings should be applicable to much larger quasars.

“This is, we think, the same mechanism at work in quasars at the cores of galaxies, where the black holes are millions of times more massive,” he said in a statement. “However, in the smaller systems, things happen much more rapidly, giving us more data.”

IMAGE: Artist’s impression of microquasar XMMU J004243.6+412519, copyright ESA / AOES Medialab