The Parkes radio telescope which is being used for observations for the Galactic All-Sky Survey.

The Parkes radio telescope in NSW.

GASS in our galaxy

The Galactic All-Sky Survey is a two-year project that will map the distribution and emissions from galactic hydrogen gas at unprecedented resolution and sensitivity.

  • 11 January 2006 | Updated 14 October 2011

Profile summary

Astronomers using the Parkes radio telescope have begun a project to map the hydrogen gas in our galaxy in unprecedented detail.

Called the Galactic All-Sky Survey (GASS), it will increase our understanding of the distribution and dynamics of gas in the Milky Way and how the disk of our galaxy interacts with the halo of gas surrounding it. 

Current activities

The GASS team hope to answer key questions about how the galaxy was formed, in particular what role the 'bits of fluff' surrounding the galaxy played in the its formation. Are these 'bits of fluff'  the building blocks leftover from the formation of the Milky Way or are they gas ejected from the galactic disk?

To answer these questions they are using the Parkes radio telescope to map the emission from hydrogen gas over the entire southern sky.  The project will take two years and nearly 2 000 hours of telescope time to complete.   

The first map of galactic hydrogen was made in the late 1960s using the Parkes radio telescope.  Now using the 21 cm Multibeam receiver the new survey will show four times more detail and reveal far fainter traces of gas than the original map.

CSIRO staff

“GASS will help us answer key questions about how the Galaxy was formed.”
Dr Naomi McClure-Griffiths, project leader.

The GASS project is led by Dr Naomi McClure-Griffiths, Senior Postdoctoral Fellow at CSIRO’s Australia Telescope National Facility with Dr Lister Staveley-Smith, Head of Astrophysics at ATNF as collaborator.


A large observational project such as GASS also involves collaborators from other institutions. These include Professor Brad Gibson from the Centre for Astrophysics and Supercomputing, Swinburne University of Technology, his PhD student, Alyson Ford who is co-supervised by Dr McClure-Griffiths and Dr DJ Pisano from Naval Research Lab in Washington and formerly at ATNF.

Others involved include Dr FJ Lockman form the National Radio Astronomy Observatory in the USA and Dr P Kalberla from University of Bonn in Germany.


GASS will allow astronomers to study the 'bits of fluff' such as high-velocity clouds (HVCs) in detail. The role of intermediate-velocity clouds in galaxy formation and disk dynamics should also be clearer.

The high resolution survey will present astronomers with a large scale global picture of our galaxy and the bridge of gas extending to the Magellanic Clouds, small neighbouring galaxies.

Once completed the entire set of GASS data will eventually be available online for all astronomers to access. It will be a valuable treasure trove of information for many years to come.

Find out more about the Australia Telescope National Facility.