31st of October 2018 |
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The slow death of the SMC |
by McClure-Griffiths et al. |
Astronomers have witnessed evidence for the slow death of a
neighbouring dwarf galaxy, the Small Magellanic Cloud, which is
gradually losing its power to form stars. High resolution images made
with data from the Australian SKA Pathfinder (ASKAP) allowed the team
to probe the interactions between the SMC and its environment. "We
were able to observe a powerful outflow of hydrogen gas from the Small
Magellanic Cloud," said Professor McClure-Griffiths from the Research
School of Astronomy and Astrophysics at ANU. "The implication is the
galaxy may eventually stop being able to form new stars if it loses
all of its gas. Galaxies that stop forming stars gradually fade away
into oblivion. It’s sort of a slow death for a galaxy if it loses all
of its gas." The result is important because it provides a possible
source of gas for the enormous Magellanic Stream that encircles the
Milky Way.
The image above shows a three-colour images of neutral hydrogen emission for the veolcity range 144 − 152 km/s, where red, green and blue are assigned sequentially to adjacent velocities. Anomalous velocity features, which include the outflows, are visible as distinctly colored features. The image spans 5 degrees, centred on a declination of -72.5 degrees. The paper is published in Nature Astronomy this week. |