A powerful radio telescope staring at a Milky Way satellite galaxy has detected thousands of hitherto unknown radio sources.
Towards the Great Magellanic Cloud, thousands of stars, supernovae and distant galaxies close to the radio’s wavelengths have been detected for the first time, data that could provide new information about the internal functioning and evolution of ‘these fascinating objects.
Everything is part of the Early Science Map of the Evolutionary Map of the Universe (EMU) that is being carried out by installing the Australian Square Kilometer Array Pathfinder (ASKAP) in Australia, one of the most sensitive radio telescopes in operation. . He is looking at Universe radio for more details on how it evolved over time.
“The new sharp, sensitive image reveals thousands of radio sources we had never seen before,” explained astronomer Clara Pennock of Keele University in the UK.
“Most of these are actually galaxies millions or even billions of light-years beyond the large Magellanic cloud. We usually see them because of the supermassive black holes in their centers that can be detected at all wavelengths, especially on the radio.But now we are also beginning to find many galaxies in which stars form at a huge rate.
“The combination of this data with previous observations of X-ray, optical and infrared telescopes will allow us to explore these galaxies in extraordinary detail.”
The Large Magellanic Cloud is a dwarf spiral galaxy orbiting the Milky Way at a distance of about 160,000 light-years. Finally, in about 2.4 billion years, it will be absorbed by the Milky Way, but for now, its proximity makes it an excellent object to know the structure of galaxies and the life cycle of stars.
The research team pointed the ASKAP antennas at this galaxy to obtain observations not only of the entire structure, but of individual objects that were there: stars, supernovae, and stellar nurseries, such as the leafy Tarantula Nebula, the most active starburst region in the Local Group of Galaxies. , forming stars at an unusually high rate.
The detections made by the team ranged from childhood stars to dead stars: bubbles of leftover material after a star has gone supernova.
“With so many stars and nebulae together, the increased sharpness of the image has been instrumental in discovering radio-emitting stars and compact nebulae in the large Magellanic cloud,” said astrophysicist Jacco van Loon, also of Keele University.
“We see all kinds of radio sources, from incipient stars to planetary nebulae that result from the death of stars like the Sun.”
The observations made represent a significant improvement in previous radio surveys of the large Magellanic cloud, according to researchers, which allow the detection of more than 50,000 radio sources. Using combined data, as well as new ASKAP observations, astronomers will be able to delve deeper into these sources for more information.
For example, planetary nebulae and supernova remnants will be the subject of future in-depth analysis.
Radio data obtained from distant galaxies behind the Large Magellanic Cloud can be used to make large-scale measurements of its Faraday rotation (the way radio waves break when they travel through the intergalactic medium) and the neutral atomic hydrogen, which can be mapped. to find out the structure of galaxies.
“It is gratifying to see these exciting results from the first observations of EMU,” said astronomer Andrew Hopkins of Macquarie University in Australia.
“The findings of this first work demonstrate the power of the ASKAP telescope to provide sensitive images over large areas of the sky, providing a captivating insight into what the full EMU survey can reveal. This research has been instrumental in enabling us to design the main survey, which we hope will begin in early 2022 “.
The research has been published in Monthly notices from the Royal Astronomical Society.