Our Milky Way swallows one of its neighbors. The analysis of the first large-scale map of the Sagittarius galaxy (named after Sagittarius in its background)
Avi Blizovsky
Direct link to this page: https://www.hayadan.org.il/sagitariusend2.html
Thousands of stars are torn from a dwarf galaxy and flow into our galaxy, the Milky Way. Astronomers say so. These "alien" stars can in time even approach our solar system.
These stars were discovered in a new survey of the entire sky. The survey was done using a technique that allowed objects in the foreground of the image to be moved to get a good view of what is happening behind the Milky Way.
Using data from the Two-Micron All Sky Survey - 2Mass, a study of the sky in the infrared light range, the astronauts can show that our Milky Way is swallowing one of its neighbors. The analysis of the first large-scale map of the Sagittarius galaxy (named after the constellation Sagittarius in its background) shows how the galaxy, which is ten thousand times smaller than our own, is being torn apart, disintegrated and swallowed by our Milky Way.
It's clear who is the bully in this meeting" says Stephen Majewski, Professor of Astronomy at the University of Virginia in the USA. "If humans had sight sensitive to infrared light, the guts of Sagittarius would be a prominent bone passing through the ocean." he says
Cosmic violence cannot be easily seen because of stars, gas and dust that get in the way. To get a better look, people use the 2Mass infrared maps and digitally remove millions of stars that are between us and the intergalactic arena, leaving only M-type giant stars. These infrared-luminous stars are a good way to monitor because they populate the galaxy in great numbers. Sagittarius and are not common for milk. "We picked up a few thousand interesting stars from a catalog of half a billion," says Prof. Michael Skrutskie, also from the University of Virginia.
By refining the maps of the sky to the desired type of stars, the Sagittarius system jumps into the field of view," said Majewski, who added: "The first complete sky map of Sagittarius shows that this galaxy is strongly interacting with the Milky Way. The new map shows that the stars and star clusters now in the outer parts of the Milky Way were ripped from Sagittarius by the Milky Way's gravity.
End of Sagittarius
Astronomers are used to seeing the formation of galaxies as an event that occurred in the distant past," says David Spergel, professor of astrophysics at Princeton University, after viewing and delving into the new substrates. "These observations reinforce the idea that galaxy formation is not a one-time event but an ongoing process."
Martin Weinberg of the University of Massachusetts, says: "After a steady and slow collection of stars by the Milky Way, Sagittarius has deteriorated to the point where it cannot maintain itself as a single unit for long. "We see Sagittarius nearing the end of its life as an independent system," he said.
Majevsky and his colleagues were surprised by the proximity of the Earth to some of the remnants of Sagittarius. "Throughout a few percent of its 240-million-year orbit around the center of the Milky Way, our solar system has passed through the orbit of the Sagittarius debris," Majewski said. To a considerable extent, stars from Sagittarius rain down into the area where we are today in the Milky Way. We need to rewrite our estimates of the Milky Way to update our theories with this contagion.
Yadan Astrophysics 2 - stars and galaxies
https://www.hayadan.org.il/BuildaGate4/general2/data_card.php?Cat=~~~646976505~~~97&SiteName=hayadan
