Nav: Home

Magellanic Clouds duo may have been a trio

September 17, 2018

Two of the closest galaxies to the Milky Way--the Large and Small Magellanic Clouds--may have had a third companion, astronomers believe.

Research published today describes how another "luminous" galaxy was likely engulfed by the Large Magellanic Cloud some three to five billion years ago.

ICRAR Masters student Benjamin Armstrong, the lead author on the study, said most stars in the Large Magellanic Cloud rotate clockwise around the centre of the galaxy.

But, unusually, some stars rotate anti-clockwise.

"For a while, it was thought that these stars might have come from its companion galaxy, the Small Magellanic Cloud," Mr Armstrong said.

"Our idea was that these stars might have come from a merger with another galaxy in the past."

Mr Armstrong, who is based at The University of Western Australia, used computer modelling to simulate galaxy mergers.

"What we found is that in this sort of merging event, you actually can get quite strong counter-rotation after a merger takes place," he said.

"This is consistent with what we see when we actually observe the galaxies."

The Magellanic Clouds can be seen in the night sky with the naked eye and have been observed by ancient cultures for thousands of years.

The Large Magellanic Cloud is a relatively small 160,000 light years away from us, while the Small Magellanic Cloud is around 200,000 light years away.

Mr Armstrong said the finding could help to explain a problem that has perplexed astronomers for years--why stars in the Large Magellanic Cloud are generally either very old or very young.

"In galaxies, there are these large objects called star clusters," he said.

"Star clusters contain many, many, many stars that are all of quite similar ages and made in similar environments.

"In the Milky Way, the star clusters are all very old.

"But in the Large Magellanic Cloud, we have very old clusters as well as ones that are very young--but nothing in between."

This is known as the 'age-gap' problem, Mr Armstrong said.

"Because in the Large Magellanic Cloud we see star formation starting again, that could be indicative of a galaxy merger taking place," he said.

Mr Armstrong said the finding could also help explain why the Large Magellanic Cloud appears to have a thick disk.

"Our work is still very preliminary but it does suggest that this sort of process could have been responsible for the thicker disk in the past," he said.

Mr Armstrong said the research was about asking pertinent questions that astronomers could start examining.

"It's about creating a new idea, a new way of looking at an old problem," he said.
-end-
The study was released in the journal Monthly Notices of the Royal Astronomical Society, published by Oxford University Press.

Original Publication

'Formation of a counter-rotating stellar population in the Large Magellanic Cloud: a Magellanic triplet system?', in the Monthly Notices of the Royal Astronomical Society published by Oxford University Press on September 18th, 2018. Available from http://www.icrar.org/clouds

More Information

The International Centre for Radio Astronomy Research (ICRAR) is a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia.

Multimedia

High-resolution images and a simulation available from http://www.icrar.org/clouds

Contacts

Benjamin Armstrong (ICRAR-UWA)
Ph: +61 466 688 016
E: Benjamin.Armstrong@icrar.org

Dr Kenji Bekki (ICRAR-UWA)
Ph: +61 8 6488 7730
E: Kenji.Bekki@icrar.org

Pete Wheeler (Media Contact, ICRAR)
Ph: +61 423 982 018
E: Pete.Wheeler@icrar.org

International Centre for Radio Astronomy Research

Related Astronomers Articles:

Canadian astronomers determine Earth's fingerprint
Two McGill University astronomers have assembled a 'fingerprint' for Earth, which could be used to identify a planet beyond our Solar System capable of supporting life.
Astronomers help wage war on cancer
Techniques developed by astronomers could help in the fight against breast and skin cancer.
Astronomers make history in a split second
In a world first, an Australian-led international team of astronomers has determined the precise location of a powerful one-off burst of cosmic radio waves.
Astronomers witness galaxy megamerger
Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of scientists has uncovered a startlingly dense concentration of 14 galaxies that are poised to merge, forming the core of what will eventually become a colossal galaxy cluster.
Double or nothing: Astronomers rethink quasar environment
Using Hyper Suprime-Cam (HSC) mounted on the Subaru Telescope, astronomers have identified nearly 200 'protoclusters,' the progenitors of galaxy clusters, in the early Universe, about 12 billion years ago, about ten times more than previously known.
Astronomers discover a star that would not die
An international team of astronomers has made a bizarre discovery; a star that refuses to stop shining.
Astronomers spun up by galaxy-shape finding
For the first time astronomers have measured how a galaxy's spin affects its shape -- something scientists have tried to do for 90 years -- using a sample of 845 galaxies.
Astronomers unveil 'heart' of Eta Carinae
An international team of astronomers has imaged the Eta Carinae star system -- a colossal binary system that consists of two massive stars orbiting each other -- including a region between the two stars in which extremely high-velocity stellar winds are colliding.
Astronomers capture best view ever of disintegrating comet
Astronomers have captured the sharpest, most detailed observations of a comet breaking apart 67 million miles from Earth, using NASA's Hubble Space Telescope.
Astronomers find the first 'wind nebula' around a magnetar
Astronomers have discovered a vast cloud of high-energy particles called a wind nebula around a rare ultra-magnetic neutron star, or magnetar, for the first time.
More Astronomers News and Astronomers Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.