A team of astronomers in Australia has produced the most extensive and detailed low-frequency radio image of the Milky Way to date, providing an unprecedented view of our galaxy. This vibrant image, created from radio wave data rather than visible light, unveils features of space that have previously remained hidden from sight.
The research was carried out by scientists at the International Centre for Radio Astronomy Research, who focused on the Southern Hemisphere perspective of our galaxy. The image employs color coding to represent different radio wavelengths, with copper and verdigris tones indicating various emissions. Professor Natasha Hurley-Walker from Curtin University emphasized the significance of the map, describing it as a milestone in astronomy that allows for the study of stellar birth and death across the southern sky.
Hurley-Walker explained, “What we”ve done here is we”ve colored those low frequencies red, and so those correspond to areas in the sky where there is more emission at those low frequencies. We”ve colored the higher frequencies blue, and those are areas of the sky where there is more emission at the high frequencies.” This innovative color scheme enables astronomers to unravel the complex astrophysical processes within our galaxy.
Over the past century, advancements in radio telescopes have revolutionized our understanding of the Milky Way. These instruments detect invisible radio waves emanating from celestial bodies, allowing researchers to map the galaxy”s structure and composition. With improvements in technology, the clarity of such images has significantly progressed.
The current project primarily targeted the Milky Way”s Galactic Plane, a dense region where a majority of stars and gas are concentrated. The research team identified nearly 98,000 radio sources, including luminous gas clouds associated with stellar nurseries known as H II regions, planetary nebulae, and even distant galaxies. A comprehensive paper detailing these findings has been published in the journal Publications of the Astronomical Society of Australia.
The GLEAM-X astronomical survey enabled the creation of this high-resolution radio image, which maps the Milky Way from the southern celestial hemisphere. Leading the project was Silvia Mantovanini, a doctoral student under Hurley-Walker, who utilized powerful supercomputers to compile over 40,000 hours of observational data. This data was collected through two extensive surveys conducted with the Murchison Widefield Array, a radio telescope located in Western Australia, far removed from human-made radio interference. Mantovanini dedicated 1.5 years to this intricate project.
Upon first seeing the image, Mantovanini expressed her excitement, stating, “Oh my God, I did it.” The newly generated image is reported to be twice as sharp and ten times more sensitive than a previous version released six years ago, encompassing double the area. This advancement allows for the examination of fainter and more distant astronomical structures.
In the new image, remnants of supernova explosions are depicted as large red circles, whereas smaller blue blobs indicate regions of active star formation. Mantovanini noted that in conventional images, these features often appear indistinguishable. However, the color differentiation in this new dataset provides clearer distinctions, enhancing the understanding of stellar evolution.
Additionally, the data sheds light on pulsars—rapidly rotating remnants of dead stars that emit steady beams of radio waves akin to lighthouses. By measuring their brightness across various frequencies, researchers can gain insights into how these enigmatic objects produce their signals and their positions within the galaxy. Mantovanini expressed anticipation about the potential discoveries other scientists could make using this valuable data.
