A team of astronomers has presented the largest low-frequency radio color image of the Milky Way, offering a remarkable new viewpoint of our galaxy from the Southern Hemisphere. This innovative image was produced by researchers at the International Centre of Radio Astronomy Research (ICRAR), significantly enhancing our understanding of stellar birth, evolution, and death.
The impressive image was crafted by Silvia Mantovanini, a Ph.D. student at Curtin University“s ICRAR node. Over the course of 18 months, she dedicated more than 40,000 hours to this project. Utilizing supercomputers at the Pawsey Supercomputing Research Centre, she processed data from two major surveys: the GaLactic and Extragalactic All-sky MWA (GLEAM) and the GLEAM eXtended (GLEAM-X). Both surveys were conducted using the Murchison Widefield Array (MWA) telescope, located at the CSIRO Murchison Radio-Astronomy Observatory on Wajarri Yamaji Country in Western Australia.
This latest image offers double the resolution of previous versions, enhances sensitivity by tenfold, and covers twice the area of the earlier GLEAM image released in 2019. The findings were detailed in the Publications of the Astronomical Society of Australia. Mantovanini remarked that the vibrant image allows for an unparalleled examination of the galaxy at low radio frequencies, which aids scientists in tracking the lifecycle of stars, from their formation to their eventual demise.
The newly captured radio image showcases the center of the Milky Way, with a color scheme indicating different frequency ranges: orange for low frequencies, green for mid-range, and blue for high frequencies. This representation enables astronomers to differentiate between the gas surrounding newly formed stars and areas generated by dead stars. The large red circles in the image signify the remnants of exploded stars, while the smaller blue smudges correspond to stellar nurseries where new stars are born. This information could lead to the discovery of thousands of previously unidentified supernova remnants in our galaxy.
The research team is also keen to enhance their understanding of pulsars—rapidly spinning, highly magnetized neutron stars that emit beams of radio waves. The pulsars” unique glow at GLEAM-X frequencies will assist scientists in pinpointing their locations and comprehending how these intriguing entities produce radiation. Associate Professor Natasha Hurley-Walker, the principal investigator of GLEAM-X, noted that the image reveals large-scale structures that are not easily observed at higher frequencies.
According to Hurley-Walker, this represents the first complete low-frequency radio image of the Southern Galactic Plane published to date. She also mentioned that only the forthcoming SKA Observatory”s SKA-Low telescope, intended to be built on Wajarri Yamaji Country in Western Australia, is expected to surpass this image in terms of both resolution and sensitivity.
Researchers at ICRAR catalogued approximately 98,000 radio sources observable from the Southern Hemisphere with the MWA telescope. This comprehensive catalog includes pulsars, planetary nebulae, compact HII regions—dense clouds of ionized gas—and distant galaxies beyond the Milky Way. The image now serves as an intricate radio portrait of our galaxy, enabling scientists to explore its structure in ways previously unattainable.
