The largest low-frequency radio-color image of the Milky Way has been produced by combining nearly 40,000 hours of GLEAM and GLEAM‑X data from the Murchison Widefield Array. The mosaic—built from 28 nights of observations in 2013–2014 and 113 nights from 2018–2020—delivers ~2× the resolution, ~10× the sensitivity and ~2× the sky area of the 2019 GLEAM map. It reveals over 98,000 radio sources and uses color to separate supernova remnants (red) from active star-forming regions (blue). The work was published Oct. 28, 2025, in Publications of the Astronomical Society of Australia.
40,000-Hour Radio Mosaic Reveals the Southern Milky Way in Vivid Color
The largest low-frequency radio-color image of the Milky Way has been produced by combining nearly 40,000 hours of GLEAM and GLEAM‑X data from the Murchison Widefield Array. The mosaic—built from 28 nights of observations in 2013–2014 and 113 nights from 2018–2020—delivers ~2× the resolution, ~10× the sensitivity and ~2× the sky area of the 2019 GLEAM map. It reveals over 98,000 radio sources and uses color to separate supernova remnants (red) from active star-forming regions (blue). The work was published Oct. 28, 2025, in Publications of the Astronomical Society of Australia.
21:54, 09.11.2025Science
Quick facts
What it is: A Southern Hemisphere low-frequency radio-color view of the Milky Way
Where: The sky around Earth, seen from the Southern Hemisphere
When published: Oct. 28–29, 2025
Overview
Because we live inside the Milky Way, we cannot capture the galaxy in one complete optical image. From Earth we see an edge-on slice: a crowded band of stars, dust and gas along the galactic plane. Low-frequency radio waves, however, can penetrate dust and reveal structures hidden from visible-light telescopes.
The new radio mosaic
A striking new composite image—assembled by Silvia Mantovanini, a PhD student at Curtin University—paints the Southern Hemisphere's galactic plane in vivid radio "colors." Mantovanini spent nearly 40,000 hours compiling and processing data from two large surveys: the GaLactic and Extragalactic All-sky MWA (GLEAM) and the follow-up GLEAM‑X.
The observations come from the Murchison Widefield Array (MWA). The original GLEAM campaign covered 28 nights in 2013–2014, and GLEAM‑X added observations across 113 nights from 2018–2020. Combining these datasets produced a mosaic with far greater depth and coverage than previous low-frequency maps.
Why it matters
According to the International Centre for Radio Astronomy Research (ICRAR), the new image delivers roughly twice the resolution, about ten times the sensitivity, and covers approximately double the sky area of the 2019 GLEAM map. The team notes that only the upcoming SKA‑Low array—an instrument of tens of thousands of antennas planned for the next decade—will surpass this combination of sensitivity and resolution.
This mosaic is the largest low-frequency radio-color image of the Milky Way produced to date. Much of the imaged region had never before been surveyed at these frequencies, making it a major milestone for low-frequency Galactic astronomy.
What the colors show
Low-frequency radio emission highlights different physical processes. In the mosaic, large red bubbles typically mark expanding shells from dead stars (supernova remnants), while compact blue regions trace ionized gas and active star-forming zones (H II regions). These color contrasts help astronomers distinguish supernova remnants, H II regions and other classes of sources.
The combined surveys catalog more than 98,000 radio sources across the southern galactic plane, including pulsars, planetary nebulae and compact star-forming regions. The map therefore captures a broad picture of the stellar life cycle—from birth in dense clouds to violent death and the resulting interactions with the surrounding medium.
Publication
The team's results were published Oct. 28, 2025, in the journal Publications of the Astronomical Society of Australia. For more images and context, see the Space Photo of the Week archives.