The Evolutionary Map of the Universe (EMU) Survey is certainly living up to expectations. It is expected to detect 40 million galaxies and appears to have discovered thousands even when it is not looking for them.
As part of an EMU Early Science Project, Clara M. Pennock and Dr Jacco van Loon used the radio observatory keen instruments to look at the Large Magellanic Cloud (LMC), one of the closest galaxies to the Milky Way. This new map of the LMC is the sharpest look we have of it in radio waves but it has also revealed tens of thousands of radio sources from nearby stars to extremely distant galaxies.
The findings are reported in the Monthly Notices of the Royal Astronomical Society. The team found 54,612 radio sources in the observation and that includes objects in the Milky Way and the LMC as well as far-away galaxies.
“The sharp and sensitive new image reveals thousands of radio sources we've never seen before. Most of these are actually galaxies millions or even billions of light years beyond the Large Magellanic Cloud,” lead author Pennock, a graduate researcher at Keele University, said in a statement.
“We typically see them because of the supermassive black holes in their centres which can be detected at all wavelengths, especially radio. But we now also start finding 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.”
The LMC is located 158,200 light-years away from Earth and is home to tens of millions of stars. As a major satellite of the Milky Way, studying it provides insights into galaxies near and far.
“With so many stars and nebulae packed together, the increased sharpness of the image has been instrumental in discovering radio emitting stars and compact nebulae in the LMC. We see all sorts of radio sources, from individual fledgling stars to planetary nebulae that result from the death of stars like the Sun,” added Dr van Loon, also at Keele University.
EMU is one of the scientific studies conducted by the Australian Square Kilometre Array Pathfinder (ASKAP). It is a precursor to the Square Kilometer Array that will become the largest radio observatory in the world being built between Australia and South Africa.
“It’s gratifying to see these exciting results coming from the early EMU observations. EMU is an incredibly ambitious project with scientific goals that range from understanding star and galaxy evolution to cosmological measurements of dark matter and dark energy, and much more,” explained leader of the EMU survey and co-author Professor Andrew Hopkins, from Macquarie University in Sydney. “The discoveries from this early work demonstrate the power of the ASKAP telescope to deliver sensitive images over wide areas of sky, offering a tantalising glimpse of what the full EMU survey may reveal. This investigation has been critical in allowing us to design the main survey, which we expect will start in early 2022.”