Unprecedented radio waves detected from nearby stars and distant galaxies


Scientists measured thousands of nearby stars and distant galaxies that had never been identified before at radio wavelengths, while studying a galactic body neighboring ours. Milky Way galaxy – the Large Magellanic Cloud.

Led by Keele University PhD student Clara M. Pennock and astrophysics lecturer Dr Jacco van Loon, the international team of researchers used the Australian Square Kilometer Array Pathfinder (ASKAP) telescope to ‘photograph’ the cloud at radio wavelengths and study the star structures within, taking some of the Cloud’s sharpest radio images ever recorded.

The Large Magellanic Cloud is a galaxy that borders our own, the Milky Way, and is known as a dwarf spiral satellite galaxy. It is located approximately 158,200 light years from Earth and is home to tens of millions of stars.

Because of its proximity to the Milky Way, it makes an excellent reference for researchers studying fundamental questions, such as star formation and the structure of galaxies.

The researchers not only took the sharpest radio images of the cloud ever recorded, but during their analysis they also studied the stars themselves that form the structure of the cloud, including the Tarantula Nebula, the region most active star formation in the local group. In addition, newly detected radio broadcasts have also been studied from distant galaxies in the background as well as stars in the foreground of our own Milky Way.

This study, published in Monthly notices from the Royal Astronomical Society, is part of the Evolutionary Map of the Universe (EMU) Early Science Project, which will observe the entire southern sky and is expected to detect around 40 million galaxies. The data will ultimately be used to give researchers a clearer picture of how galaxies and their stars have evolved over time.

Senior author Clara Pennock from Keele University said: “The new crisp and sensitive image reveals thousands of radio sources that we have never seen before. Most of them are in fact 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 which can be detected at all wavelengths, especially radio. But now we are also starting to find many galaxies in which stars are forming at a tremendous rate. Combining this data with previous observations from X-ray, optical and infrared telescopes will allow us to explore these galaxies in extraordinary detail.

Dr Jacco van Loon, Astrophysics Lecturer at Keele University, said: ‘With so many stars and nebulae crowded together, the increased sharpness of the image was instrumental in the discovery of star-emitting stars. radio and compact nebulae in the LMC. We see all kinds of radio sources, from individual nascent stars to planetary nebulae that result from the death of stars like the Sun.

Co-author Professor Andrew Hopkins, Macquarie University in Sydney, Australia, responsible for the EMU survey, added: “It is gratifying to see these exciting results emerging from the early observations of EMU. EMU is an incredibly ambitious project with scientific goals that range from understanding the evolution of stars and galaxies to cosmological measurements of dark matter and dark energy, and much more. The findings from this early work demonstrate the power of the ASKAP telescope to deliver sensitive images over large areas of the sky, offering a tantalizing glimpse of what the full EMU investigation can reveal. This survey has been essential in enabling us to design the main survey, which we hope will begin in early 2022. ”

Reference: “The ASKAP-EMU Early Science Project: 888 MHz radio continuum survey of the Large Magellanic Cloud” by Clara M Pennock, Jacco Th van Loon, Miroslav D Filipović, Heinz Andernach, Frank Haberl, Roland Kothes, Emil Lenc, Lawrence Rudnick , Sarah V White, Claudia Agliozzo, Sonia Antón, Ivan Bojičić, Dominik J Bomans, Jordan D Collier, Evan J Crawford, Andrew M Hopkins, Kanapathippillai Jeganathan, Patrick J Kavanagh, Bärbel S Koribalski, Denis Leahy, Pierre Maggi, Chandreyee Maitra, Josh Marvil, Michał J Michałowski, Ray P Norris, Joana M Oliveira, Jeffrey L Payne, Hidetoshi Sano, Manami Sasaki, Lister Staveley-Smith and Eleni Vardoulaki, July 2, 2021, Monthly notices from the Royal Astronomical Society.
DOI: 10.1093 / mnras / stab1858

ASKAP is owned by the Commonwealth of Nations Scientific and Industrial Research Organization (CSIRO). ASKAP is an array of 36 satellite dishes with a greater separation of six kilometers, which, when combined, act as a telescope of approximately 4000 square meters.

ASKAP uses a new technique called phased array feeding (PAF), and each of the 36 antennas has a PAF that allows the telescope to look at the sky in 36 directions at a time, increasing the amount of sky that can be observed at a time. 30 square degrees on the sky and thus, increasing the survey speed.

ASKAP is a forerunner of SKA, the world’s largest radio telescope, currently under construction in South Africa and Australia, and headquartered at Jodrell Bank Observatory near Manchester, UK.


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