Astronomers have observed for the first time stars forming within powerful outflows of material blasted out from supermassive black holes at the cores of galaxies.
"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," said team leader Roberto Maiolino from University of Cambridge.
"Our results are exciting because they show unambiguously that stars are being created inside these outflows," Maiolino added.
The discovery, published in the journal Nature, has many consequences for understanding galaxy properties and evolution.
The discovery provides new and exciting information that could better our understanding of some astrophysics, including how certain galaxies obtain their shapes; how intergalactic space becomes enriched with heavy elements; and even from where unexplained cosmic infrared background radiation may arise.
The group of European astronomers used the MUSE and X-shooter instruments on the Very Large Telescope (VLT) at European Southern Observatory's Paranal Observatory in Chile to study an ongoing collision between two galaxies, known collectively as IRAS F23128-5919, that lie around 600 million light-years from Earth.
Observing the colossal winds of material — or outflows — originating near the supermassive black hole at the heart of the pair's southern galaxy, the researchers found the first clear evidence that stars are being born within them.
Such galactic outflows are driven by the huge energy output from the active and turbulent centres of galaxies.
Supermassive black holes lurk in the cores of most galaxies, and when they gobble up matter they also heat the surrounding gas and expel it from the host galaxy in powerful, dense winds.
"The stars that form in the wind close to the galaxy centre might slow down and even start heading back inwards, but the stars that form further out in the flow experience less deceleration and can even fly off out of the galaxy altogether," study co-author Helen Russell from Institute of Astronomy, University of Cambridge, explained.