Distant starbursts are warmer than expected

Extremely distant galaxies are hard to find, and even more difficult to confirm. With observations from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile astronomers at Durham have now detected ten new galaxies at redshift z=4.4-4.6 (12.3 billion light years away). These galaxies are forming stars at phenomenal rates – thousands of solar masses per year – and their star formation regions are surrounded by a large amount of dust. The high rate of star formation has heated up this dust to more than 50K – nearly twice as warm as similar galaxies that are closer to Earth.

This sample of ten galaxies places constraints on how many more galaxies of their kind may exist. We now think that about 7% of the highly star-forming, dusty galaxy population lie between z=4 and z=5 (12.1-12.5 billion light years away) – meaning there are a lot more out there to discover.
Images of some of the new distant starbursts
The figure shows true-colour images of four of the newly-confirmed distant highly star-forming galaxies. These galaxies appear red because they are far away, but also because they have a lot of dust in them. The orange contours show the new ALMA detections.

Link to the original research paper: https://arxiv.org/abs/1805.05363

Contacts from CEA, Durham:

Elizabeth Cooke

Ian Smail

Mark Swinbank

Stuart Stach

Fangxia An

Bitten Gullberg

Julie Wardlow