From ICRAR: “Astronomers probe swirling particles in halo of starburst galaxy’

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International Centre for Radio Astronomy Research

March 28, 2017

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NGC253 starburst galaxy in optical (green; SINGG Survey) and radio (red; GLEAM) wavelengths. The H-alpha line emission, which indicates regions of active star formation, is highlighted in blue (SINGG Survey; Meurer+2006). Credits: A.D. Kapinska, G. Meurer. ICRAR/UWA/CAASTRO.

Astronomers have used a radio telescope in outback Western Australia to see the halo of a nearby starburst galaxy in unprecedented detail.

A starburst galaxy is a galaxy experiencing a period of intense star formation and this one, known as NGC 253 or the Sculptor Galaxy, is approximately 11.5 million light-years from Earth.

“The Sculptor Galaxy is currently forming stars at a rate of five solar masses each year, which is a many times faster than our own Milky Way,” said lead researcher Dr Anna Kapinska, from The University of Western Australia and the International Centre for Radio Astronomy Research (ICRAR) in Perth.

The Sculptor Galaxy has an enormous halo of gas, dust and stars, which had not been observed before at frequencies below 300 MHz. The halo originates from galactic “fountains” caused by star formation in the disk and a super-wind coming from the galaxy’s core.

The study used data from the ‘GaLactic and Extragalactic All-sky MWA’, or ‘GLEAM’ survey, which was observed by the Murchison Widefield Array (MWA) radio telescope located in remote Western Australia.

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Murchison Widefield Array (MWA) radio telescope

“With the GLEAM survey we were able, for the first time, to see this galaxy in its full glory with unprecedented sensitivity at low radio frequencies,” said Dr Kapinska.

“We could see radio emission from electrons accelerated by supernova explosions spiralling in magnetic fields, and absorption by dense electron-ion plasma clouds —it’s absolutely fascinating.”

The MWA is a precursor to the Square Kilometre Array (SKA) radio telescope, part of which will be built in Western Australia in the next decade.

Co-author Professor Lister Staveley-Smith, from ICRAR and the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), said the SKA will be the largest radio telescope in the world and will be capable of discovering many new star-forming galaxies when it comes online.

“But before we’re ready to conduct a large-scale survey of star-forming and starburst galaxies with the SKA we need to know as much as possible about these galaxies and what triggers their extreme rate of star formation,” he said.

PUBLICATION DETAILS

Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies, published in the Astrophysical Journal on March 28th, 2017.

See the full article here .

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ICRAR is an equal joint venture between Curtin University and The University of Western Australia with funding support from the State Government of Western Australia. The Centre’s headquarters are located at UWA, with research nodes at both UWA and the Curtin Institute for Radio Astronomy (CIRA).
ICRAR has strong support from the government of Australia and is working closely with industry and the astronomy community, including CSIRO and the Australian Telescope National Facility, iVEC, and the international SKA Project Office (SPO), based in the UK.

ICRAR is:

Playing a key role in the international Square Kilometre Array (SKA) project, the world’s biggest ground-based telescope array.

SKA Square Kilometer Array
Attracting some of the world’s leading researchers in radio astronomy, who will also contribute to national and international scientific and technical programs for SKA and ASKAP.
Creating a collaborative environment for scientists and engineers to engage and work with industry to produce studies, prototypes and systems linked to the overall scientific success of the SKA, MWA and ASKAP.

SKA Murchison Widefield Array
A Small part of the Murchison Widefield Array

Enhancing Australia’s position in the international SKA program by contributing to the development process for the SKA in scientific, technological and operational areas.
Promoting scientific, technical, commercial and educational opportunities through public outreach, educational material, training students and collaborative developments with national and international educational organisations.
Establishing and maintaining a pool of emerging and top-level scientists and technologists in the disciplines related to radio astronomy through appointments and training.
Making world-class contributions to SKA science, with emphasis on the signature science themes associated with surveys for neutral hydrogen and variable (transient) radio sources.
Making world-class contributions to SKA capability with respect to developments in the areas of Data Intensive Science and support for the Murchison Radio-astronomy Observatory.

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