Sausage broken in the milky way 10 billion years ago

It sounds like some kind of very strange cuisine involving a sausage and a Milky Way.

A mass of stars nicknamed the Sausage Galaxy had a frontal collision with the Milky Way 8 to 10 billion years ago. scientists using ESA's Gaia space telescope data.

Astronomers have searched for the source of "disturbances" in our galaxy revealed by Gaia in his latest data release, and now they think they have found the culprit, which has a distinctive character. The cosmic shock between the sausage – a dwarf galaxy – and ours has been a defining event in the early history of the Milky Way, and is probably responsible for its internal bulge and its outer halo.

Sausage Stars: When looking at the velocity distribution of stars in the Milky Way, the stars of the Sausage galaxy form a characteristic sausage shape. This unique shape is caused by the strong radial movements of the stars. As the sun is in the center of this huge cloud of stars, the cast does not include the slow-moving stars that are currently making a U-turn towards the center of the galaxy.

"The collision shredded the dwarf, letting his stars move in very radial orbits" which are long and narrow like needles, said Vasily Belokurov of the University of Cambridge and the Center for Computational Astrophysics at the Flatiron Institute in New York. The paths of the stars take them "very near the center of our galaxy.This is a telltale sign that the dwarf galaxy has entered a really eccentric orbit and its fate has been sealed."

The discovery was possible because Gaia has tracked the position and speed of more than a billion stars in our region of the galaxy, accounting for about 1% of the galactic total but sufficient to draw meaningful conclusions about the story from our region of origin.

The stars' paths of galactic fusion have earned them the nickname "Gaia Sausage," says Wyn Evans of the University of Cambridge. "We have traced the velocities of the stars, and the shape of the sausage has just jumped on us.As the smaller galaxy separated, its stars were thrown into very radial orbits. which remains of the last major merger of the Milky Way. "

The Milky Way continues to collide with other galaxies, such as the dwarf Sagittarius's tiny galaxy. However, the galaxy of sausage was much more massive. Its total mass of gas, stars and dark matter was more than 10 billion times the mass of our Sun. When the sausage squeezed into the young Milky Way, its piercing trajectory caused chaos. The Milky Way disk was probably puffy or even fractured following impact and should have grown back while sausage debris was scattered all around the inner parts of the Milky Way, creating the & quot; bulge & # 39; ; in the center of the galaxy and the & # 39; stellar & # 39; surrounding. halo. & # 39;