Dark hearts of hidden galaxies revealed

Astronomers from the UK, Germany and the Netherlands are peering into the dark hearts of bright galaxies to learn more about how our own Universe formed.

JCMT on Mauna Kea, Hawaii
Credit: JAC

Luminous and ultra-luminous infrared galaxies emit enormous amounts of energy at infrared and far-infrared wavelengths. These ‘starburst’ galaxies are more common in the younger, more distant universe and are believed to represent an important step in the evolution of galaxies.

The power source behind this energy output, however, is hidden by dust and molecular clouds and cannot be seen at optical wavelengths. Astronomers therefore use the Hawaii-based James Clerk Maxwell Telescope (JCMT) – the world's largest, single-dish submillimetre-wave telescope.

“The submillimetre waveband,” explained Dr Kate Izaak, “provides a unique viewing window through which we can see deep into these galaxies – past the dust, and into the regions hosting the prodigious star formation and supermassive black hole activity which power these energetic galaxies.”

Dr Izaak, from Cardiff University, is part of an international team working with the telescope. She used the recently-commissioned instrument HARP (Heterodyne Array Receiver Programme) to search for faint emission lines of molecules such as carbon monoxide and hydrogen cyanide. These molecular fingerprints help build up a detailed picture of the gases that fuel star formation inside these galaxies.

“HARP is an imaging array receiver and is the first of its kind in the world,” she said. “The fact that we were able to detect very faint lines is a tribute to its high sensitivity," said JCMT Director, Professor Gary Davis.

• UK astronomers are helping towards understanding how our Universe was formed.
  
  
• UK scientists rank second in the world in Space Science (including astronomy) in terms of the productivity and impact of their research.