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Astronomers have discovered an ancient event in the history of space that involved a frontal collision between the Milky Way and a smaller object, nicknamed the galaxy "sausage".
Discovered by an international team of astronomers, the cosmic crash apparently a "milestone event" in the ancient history of the Milky Way and reshaped the structure of the galaxy, shaping both its inner bulge and its external halo.
In a new study, astronomers propose that it pbaded around eight billion ten billion years ago, with an unknown dwarf galaxy that crashed in our own Milky Way but that did not survive the impact. Astronomers said that it quickly collapsed, and the wreckage is scattered all around us.
"The collision shredded the dwarf, letting its stars move in very radial orbits that are long and narrow like needles," says Vasily Belokurov. the University of Cambridge and the Center for Computational Astrophysics at the Flatiron Institute in New York.
"The trajectories of the stars take them very close to the center of our galaxy. It's a telltale sign that the dwarf galaxy has entered a really eccentric orbit and its fate has been sealed."
To discover the event, Belokurov and his colleagues used data from the Gaia satellite of the European Space Agency, a spacecraft that maps the stellar contents of our galaxy and records the journeys of the stars during of their journey through the Milky Way.
And it is thanks to Gaia that astronomers now know the positions and trajectories of our celestial neighbors with unprecedented accuracy.
Professor Wyn Evans of the Institute of Astronomy at the University of Cambridge explained that these are the paths of the stars. the galactic fusion that earned the nickname "Gaia sausage".
"We traced the velocities of the stars, and the shape of the sausage jumped over us.When the smallest galaxy shattered, its stars were thrown into very radial orbits. Are the remnants of the last great fusion of the Milky Way, "he said.
The new research also identified at least eight large spherical clusters of stars called globular clusters that were introduced in the milky way by the galaxy of sausage Small galaxies usually do not have their own globular clusters, so the galaxy of sausages must have been large enough to accommodate a collection of clusters.
"Good that there have been many dwarf satellites falling on the biggest Milky Way of all, "adds Sergey Koposov of Carnegie Mellon University, who has been studying the kinematics of sausage stars and globular clusters since some time.
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