[ad_1]
Astronomers have witnessed, in every detail so far, a brutal David-vs-Goliath clash between two nearby galaxies that are tearing themselves apart and throwing them into the gaseous Magellanic Stream, a cosmic river of blood surrounding our Milky Way.
The new ANU-led study investigated the violent smothering between large and small magellanic clouds, dwarf galaxies on the periphery of the Milky Way and visible at night with the naked eye in the hemisphere South.
The principal investigator, Dr. Dougal Mackey of the ANU, said that the team had created a very low star map on the outer edges of the clouds with the help of the Dark energy camera on the 4 m Blanco telescope in Chile and revealed that the clouds had repeated interactions with each other. billions of years.
"This fight is very similar to the one David and Goliath could have had if the little guy had not had such a chance with his slingshot," said Dr. Mackey of the School of Astronomy and Astrophysics Research. from ANU.
"The Great Magellanic Cloud really beats its smallest companion – the outer parts of the Little Cloud are greatly elongated both towards and away from the Great Cloud."
The distribution of stars of different ages in the small cloud indicates possible unpleasant encounters with the large cloud that extends over several billion years.
"The Great Cloud has absolutely not left these fights, as the nearest side of the Little Magellanic Cloud is highly distorted and pruned, and other parts of its periphery present major distortions."
Mackey said the results provided further evidence that the vicious and continuous conflicts between the two clouds had created Magellan flow.
"The clouds will finally be completely consumed by the Milky Way, but we would like to know how much time they have left and what kind of impact they will have before their ultimate destruction," he said.
"We have also revealed, to the smallest detail so far, the formation of young stars in a magellanic current between the clouds.This part of the current is known as the Magellanic Bridge."
Mackey said the team also discovered a tiny galaxy previously unknown, called Hydrus I, sitting between the two clouds.
"This galaxy is part of a class known as the ultra-weak dwarves, whose existence was discovered only 10 years ago. They are dwarf galaxies of very low light, but they still contain a lot of dark matter, "he said.
There is a broad scientific consensus that dark matter – a subject that scientists can not see – is widely present in the Universe and helps to explain how galaxies stand together rather than shatter when They turn.
"Hydrus I is likely to be a cloud satellite or two that has fallen into the Milky Way with its larger companions," said Dr. Mackey.
Astronomers from the United Kingdom and the United States supported the study, which is published in the Astrophysical Journal Letters.
More information:
Dougal Mackey et al. Substructures and tidal distortions in Magellan's stellar periphery, The astrophysical journal (2018). DOI: 10.3847 / 2041-8213 / aac175
Astronomers have witnessed, in every detail so far, a brutal David-vs-Goliath clash between two nearby galaxies that are tearing themselves apart and throwing them into the gaseous Magellanic Stream, a cosmic river of blood surrounding our Milky Way.
The new ANU-led study investigated the violent smothering between large and small magellanic clouds, dwarf galaxies on the periphery of the Milky Way and visible at night with the naked eye in the hemisphere South.
The principal investigator, Dr. Dougal Mackey of the ANU, said that the team had created a very low star map on the outer edges of the clouds with the help of the Dark energy camera on the 4 m Blanco telescope in Chile and revealed that the clouds had repeated interactions with each other. billions of years.
"This fight is very similar to the one David and Goliath could have had if the little guy had not had such a chance with his slingshot," said Dr. Mackey of the School of Astronomy and Astrophysics Research. from ANU.
"The Great Magellanic Cloud really beats its smallest companion – the outer parts of the Little Cloud are greatly elongated both towards and away from the Great Cloud."
The distribution of stars of different ages in the small cloud indicates possible unpleasant encounters with the large cloud that extends over several billion years.
"The Great Cloud has absolutely not left these fights, as the nearest side of the Little Magellanic Cloud is highly distorted and pruned, and other parts of its periphery present major distortions."
Mackey said the results provided further evidence that the vicious and continuous conflicts between the two clouds had created Magellan flow.
"The clouds will finally be completely consumed by the Milky Way, but we would like to know how much time they have left and what kind of impact they will have before their ultimate destruction," he said.
"We have also revealed, to the smallest detail so far, the formation of young stars in a magellanic current between the clouds.This part of the current is known as the Magellanic Bridge."
Mackey said the team also discovered a tiny galaxy previously unknown, called Hydrus I, sitting between the two clouds.
"This galaxy is part of a class known as the ultra-weak dwarves, whose existence was discovered only 10 years ago. They are dwarf galaxies of very low light, but they still contain a lot of dark matter, "he said.
There is a broad scientific consensus that dark matter – a subject that scientists can not see – is widely present in the Universe and helps to explain how galaxies stand together rather than shatter when They turn.
"Hydrus I is likely to be a cloud satellite or two that has fallen into the Milky Way with its larger companions," said Dr. Mackey.
Astronomers from the United Kingdom and the United States supported the study, which is published in the Astrophysical Journal Letters.
More information:
Dougal Mackey et al. Substructures and tidal distortions in Magellan's stellar periphery, The astrophysical journal (2018). DOI: 10.3847 / 2041-8213 / aac175
6
Source link
