Stars born in a black hole's breath

A new type of star formation has been observed in the winds blowing from a galaxy's supermassive black hole.

An artist's impression of stars forming within a galaxy's outflows. Credit: ESO/E. Kornmesse
Published: March 27, 2017 at 12:00 pm
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Stars are being born in the powerful outflows exhaled by supermassive black holes.


Observations taken by ESO’s Very Large Telescope (VLT) have recently provided the first confirmation that stars can form in this extreme environment.

A UK-led team of researchers turned the VLT towards a pair of colliding galaxies collectively known as IRAS F23128-5919.

The astronomers observed the colossal ejections of material, known as outflows, that are created when material falls in towards the supermassive black hole.

The ensuing turbulence causes the gas to superheat and be expelled from the host galaxy in a powerful wind.

First, the team studied the light emitted from the outflows and found key signatures indicating young stars were present.

Later the group were able to directly detect stars within the winds, finding them to be less than a few tens of millions of years old, mere infants in stellar terms.

“Astronomers have thought for a while that conditions within these outflows could be right for star formation, but no one has seen it actually happening as it’s a very difficult observation,” says Roberto Maiolino, an astronomer from University of Cambridge who led the team.

“Our results are exciting because they show unambiguously that stars are being created inside these outflows.

Forged in the inferno of these turbulent outflows, these stars seem brighter and hotter than their cousins who were born in more sedate stellar nurseries.

Several of them are moving at great speed away from the galaxy centre, suggesting they are caught in a stream of fast moving material.

It’s possible that some may be thrown out of the galaxy entirely.


“If star formation really is occurring in most galactic outflows, as some theories predict, then this would provide a completely new scenario for our understanding of galaxy evolution,” says Maiolino.


Ezzy Pearson is the News Editor of BBC Sky at Night Magazine. Her first book about the history of robotic planetary landers is out now from The History Press.


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