Autumn 2023 ASKAP update

A new radio astronomy image, showcasing the places of star births and deaths, is one of the most detailed radio image yet of our galaxy. It was captured by ASKAP working together with our Parkes radio telescope, Murriyang, which is on Wiradjuri Country.

It was an international effort, with researchers collaborating from across Australia, plus Italy, China and Canada. The clarity of the image is helping astronomers answer the question, “where are all the supernova remnants?”.

Animation moving from the ASKAP image (darkest), to the combined image, to the image produced by Parkes, Murriyang (fuzzy). Both are needed to fully understand what is happening in our Milky Way. Credit: E. Carretti (INAF), R. Kothes (NRC) and the PEGASUS team.

This question has troubled astronomers for some time. Supernova remnants are what’s left when a large star dies: it explodes dramatically, and the shockwave becomes an expanding bubble only visible to radio telescopes.

On the way to answering big questions

Due to the age and density of the Milky Way, we should see the remnants of many, many stars that have lived and died. However, telescopes have not been sensitive enough to detect these remnants.

It is the resolution of ASKAP to see the detailed outlines of the supernova remnants, and the capability of Parkes to see thinly-spread gas clouds between the stars, that is unveiling the history of our Milky Way galaxy. Scientists have discovered over twenty new possible supernova remnants from combining the data from ASKAP and Parkes. Only seven were previously known.

Sightings of supernovas in the sky have been recorded for millennia, and oral stories of bright stars that disappear from the sky help telescope operators know where to look. However, many of these stars weren’t bright enough for human eyes or exploded during a time before humans.

It is estimated that there may be about 1500 more supernova remnants in the galaxy that astronomers haven’t discovered yet. Finding the missing remnants will help us unlock more of an understanding of our galaxy and its history. With this image being only 1% of the galaxy, there is much more to come. It is just the start of this project to observe our Milky Way with both telescopes so, as always, watch this space!

Left: The Milky Way as seen by ASKAP; right: Data from ASKAP and Parkes, Murriyang, combined. Credit: E. Carretti (INAF), R. Kothes (NRC) and the PEGASUS team.

You can read more about this project and hear from some of the scientists on our CSIRO news webpage.

ASKAP and Parkes are owned and operated by CSIRO as part of the Australia Telescope National Facility. We acknowledge the Wajarri Yamaji people as the Traditional Owners and native title holders of Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory site, where ASKAP is located, and the Wiradjuri people as the traditional owners of the Parkes Observatory site.

Aidan Hotan, ASKAP Principal Research Scientist, CSIRO and

Rachel Rayner, Senior Communications Advisor, CSIRO