Atomic hydrogen gas identified in far-off galaxies at 'record-breaking' distances

Astronomers were recently able to detect atomic hydrogen gas emission in galaxies which are 3 billion light years away from Earth and it broke the previous record distance which was 500 million light years.

Using the 305-m diameter Arecibo radio telescope in Puerto Rico, Dr Barbara Catinella and Dr Luca Cortese, from Swinburne University of Technology in Australia, measured the hydrogen gas content of nearly 40 galaxies at distances of up to three billion light years. By doing so, the two scientists found a unique population of galaxies hosting huge reservoirs of hydrogen gas, the fuel for forming new stars like Earth's Sun.

These very gas-rich systems each contain between 20 and 80 billion times the mass of the Sun in atomic gas. Such galaxies are rare, but astronomers believe that they were more common in the past, when the Universe was younger. Dr Catinella said that atomic hydrogen gas was the fuel out of which new stars are formed; hence it would be a crucial component to study in order to understand how galaxies form and evolve.

Further studies will seek to understand why these galaxies have not yet converted a great part of their gas into stars. The SKA and its pathfinders will be the key to solving this mystery.

The study is published in the journal Monthly 'Notices of the Royal Astronomical Society'.