From ANU: “Astronomers create most detailed radio image of nearby dwarf galaxy”

ANU Australian National University Bloc

Australian National University

28 November 2017

Will Wright
+61 2 6125 7979
media@anu.edu.au

New imaging hints at a violent past and a fatal future for the Small Magellanic cloud. COSMOS

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The new radio image of the Small Magellanic Cloud. ANU/CSIRO

Astronomers at ANU have created the most detailed radio image of nearby dwarf galaxy, the Small Magellanic Cloud, revealing secrets of how it formed and how it is likely to evolve.

SKA/ASKAP radio telescope at the Murchison Radio-astronomy Observatory (MRO) in Mid West region of Western Australia

This image was taken by CSIRO’s powerful new radio telescope, the Australian Square Kilometre Array Pathfinder (ASKAP), and its innovative radio camera technology, known as phased array feeds.

SKA ASKAP Phased Array

The Small Magellanic Cloud, which is a tiny fraction of the size and mass of the Milky Way, is one of our nearest galactic neighbours and visible to the naked eye in the southern sky.

Small Magellanic Cloud. NASA/ESA Hubble and ESO/Digitized Sky Survey 2

Co-lead researcher Professor Naomi McClure-Griffiths said the complex structure of the dwarf galaxy likely resulted, in part, from interactions with its companion, the Large Magellanic Cloud, and the Milky Way.

Large Magellanic Cloud. Adrian Pingstone December 2003

“The new image captured by CSIRO’s Australian Square Kilometre Array Pathfinder telescope reveals more gas around the edges of the galaxy, indicating a very dynamic past for the Small Magellanic Cloud,” said Professor McClure-Griffiths from the ANU Research School of Astronomy and Astrophysics.

“These features are more than three times smaller than we were able to see before and allow us to probe the detailed interaction of the small galaxy and its environment.”

Professor McClure-Griffiths said distortions to the Small Magellanic Cloud occurred because of its interactions with the larger galaxies and because of its own star explosions that push gas out of the galaxy.

“The outlook for this dwarf galaxy is not good, as it’s likely to eventually be gobbled up by our Milky Way,” she said.

“Together, the Magellanic Clouds are characterised by their distorted structures, a bridge of material that connects them, and an enormous stream of hydrogen gas that trails behind their orbit – a bit like a comet.”

Magellanic Bridge ESA_Gaia satellite. Image credit V. Belokurov D. Erkal A. Mellinger.

The Small Magellanic Cloud has been studied extensively in the past few years by infrared telescopes such as NASA’s Spitzer Space Telescope and ESA’s Herschel telescope, which study the dust and stars within the galaxy.

NASA/Spitzer Infrared Telescope

ESA/Herschel spacecraft

“The new radio image finally reaches the same level of detail as those infrared images, but on a very different component of the galaxy’s make-up: its hydrogen gas,” Professor McClure-Griffiths said.

“Hydrogen is the fundamental building block of all galaxies and shows off the more extended structure of a galaxy than its stars and dust.”

CSIRO spokesperson, Dr Philip Edwards, said: “This stunning image showcases the wide field of view of the ASKAP telescope, and augurs well for when the full array will come on-line next year.”

See the full article here .

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