EMU Project Takes Step Forward with First ASKAP Datasets

Two separate papers report the first radio observations of the galactic plane as made by the Australian SKA Pathfinder, or the ASKAP.

A group of astronomers led by members of the Italian National Institute of Astrophysics (INAF) and Macquarie University in Australia used the ASKAP, a radio telescope array developed and managed by the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia's science agency.

The region mapped from the first reports of the ASKAP includes the entire region of the Stellar Continuum Originating from Radio Physics In Ourgalaxy (SCORPIO) field survey, which is a prior exploration project to generate an Evolutionary Map of the Universe (EMU). The EMU project will be using the ASKAP telescope to create a census of radio sources from the sky, particularly those from the southern hemisphere.

One of the reports, titled "A first glimpse at the Galactic Plane with the ASKAP: the SCORPIO field," appears in the Monthly Notices of the Royal Astronomical Society," detail the radio observations toward the galactic plane. The other paper, "Evolutionary map of the Universe (EMU): Compact radio sources in the SCORPIO field towards the galactic plane," presents a regional observation during the early science program of the ASKAP.

ASKAP's First Glimpse at the SCORPIO Field

The ASKAP observations in the newly accepted manuscript at the Monthly Notices were conducted back in January 2018, using a central frequency of 912 MHz. It used an array of 15 operational antennas and covered about 40 square degrees across three different pointings. It generated a final image that contained 3545 candidate sources, with about 75 percent of these items being point sources.

As a part of the ASKAP preliminary activities in preparation for its EMU project, the radio astronomers directed the Australian pathfinder toward the tail of the Scorpion. During this time, the interferometer wasn't fully developed since only 15 out of 36 antennas of the array were operational. The resulting image included the so-called SCORPIO field, being its first generated result with help from the team from INAF that used the Australia Telescope Compact Array (ATCA).

Through the use of the ASKAP, radio astronomers can now detect more sources that were previously identified as radio-quiet and might lead to the discovery of more extended, previously unclassified sources. These unclassified sources, belonging to immense galactic bubbles, could offer a new sample for identifying the remains of supernovas.

The Future of the EMU Project

"SCORPIO is the only galactic field observed so far with ASKAP. It is especially important for the characterization of these galactic populations because they provide a solid foundation to help design some aspects of the EMU survey," says Grazia Umana, principal investigator of the SURVEY and first author of the published article, in the news release from Macquarie University. "In addition to discovering numerous galactic radio sources, these observations have highlighted the unique feature of ASKAP to map complex objects at a range of angular scales, critical in studying the galactic plane."

The EMU project is an international collaborative effort, which according to the CSIRO Australia Telescope National Facility website, aims to detect 70 million radio sources in addition to about 2.5 million currently identified radio sources. This is expected to provide insights into how stars and galaxies first formed and how they evolved to their current states.

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