Astronomers have unveiled the largest low-frequency radio image of the Milky Way, offering unprecedented views of star formation and stellar remnants. Created using data from Australian telescopes, the image reveals hidden galactic structures in vivid radio colors. This breakthrough enhances understanding of the galaxy's star life cycles.
Astronomers at the International Centre of Radio Astronomy Research (ICRAR) have produced an extraordinary low-frequency radio image of the Milky Way, capturing the galaxy from the Southern Hemisphere across various radio wavelengths. The image, assembled by PhD student Silvia Mantovanini at Curtin University's ICRAR node, took 18 months to complete and required about 1 million CPU hours on supercomputers at the Pawsey Supercomputing Research Centre.
The data originates from two major surveys using the Murchison Widefield Array (MWA) telescope at the CSIRO Murchison Radio-Astronomy Observatory in Western Australia. The GaLactic and Extragalactic All-sky MWA (GLEAM) survey collected observations over 28 nights in 2013 and 2014, while its follow-up, GLEAM-X, spanned 113 nights from 2018 to 2020. Compared to the 2019 GLEAM release, this new image offers twice the resolution, ten times the sensitivity, and covers twice the sky area.
"This vibrant image delivers an unparalleled perspective of our Galaxy at low radio frequencies," Mantovanini said. It distinguishes supernova remnants—expanding clouds from exploded stars, shown as large red circles—from stellar nurseries, the blue regions where new stars form. The work aids in identifying thousands of potential undiscovered remnants and studying pulsars, the spinning cores of massive stars.
Associate Professor Natasha Hurley-Walker, principal investigator of GLEAM-X, noted, "This low-frequency image allows us to unveil large astrophysical structures in our Galaxy that are difficult to image at higher frequencies." She emphasized that no prior low-frequency radio image of the entire Southern Galactic Plane existed, marking a milestone. The surveys cataloged around 98,000 radio sources, including pulsars, planetary nebulae, and distant galaxies.
Looking ahead, Hurley-Walker highlighted that only the upcoming SKA-Low telescope in Western Australia will exceed this image's detail in the next decade.