The scientists determined their findings after measuring the motions of nearly 7,500 stars in the Andromeda Galaxy’s inner circle.
Hitekno.com – Studying the stars is a very complicated process, especially when interesting events occurred many centuries ago.
However, a team of astrophysicists was lucky enough to use ultra-modern technology to capture processes in a neighboring galaxy that could reveal details of our galaxy’s past.
According to Sputnik Newsan international team of scientists have found new evidence showing the mass migration of celestial bodies migrating from one galaxy to another, marking a first for astronomers.
The astronomers used data from the US Department of Energy’s Dark Energy Spectroscopy Instrument (DESI), from the four-metre Nicholas U. Mayall Telescope at Kitt Peak National Observatory.
Scientists determined their findings after measuring the motions of nearly 7,500 stars in the inner circle of the Andromeda Galaxy, also known as Messier 31 (M31). As a result, astronomers discover controlling patterns in the positions and motions of the stars.
It turns out that when these stars were born, they were part of another galaxy, and then merged with M31 about 2 billion years ago.
“Our new observations of the Milky Way’s nearest large galactic neighbor, the Andromeda Galaxy, reveal evidence of galactic immigration events in great detail,” said lead author Arjun Dey.
“Although the night sky may appear unchanging, the universe is a dynamic place. Galaxies like M31 and our Milky Way were built from the building blocks of many smaller galaxies over the course of cosmic history.”
Most of the Milky Way’s stars formed in other galaxies and migrated in massive mergers between 8 and 10 billion years ago.
Thus, studying the remnants of a similar but more recent galactic merger in M31 could help scientists investigate our galaxy’s past.
“We’ve never seen this so clearly in the motion of a star, nor have we seen some of the structures that result from this merger,” said Sergey Koposov, an astrophysicist at the University of Edinburgh and co-author of the paper.
“Our emerging picture is that the history of the Andromeda Galaxy is similar to that of our own Galaxy, the Milky Way. The inner rings of both galaxies were dominated by a single immigration event.”
Scientists also note that such surveys are only possible thanks to DESI, which was built to map tens of millions of galaxies in the nearby Universe.
“This science is not possible at any other facility in the world. DESI’s extraordinary efficiency, throughput and field of view make it the best system in the world for surveying stars in the Andromeda Galaxy,” said Dey.
“In just a few hours of observation time, DESI was able to surpass more than a decade of spectroscopy with much larger telescopes.”
The instrument is still the most powerful multi-object survey spectrograph in the world. Among other features, it can measure the spectra of more than 100,000 galaxies overnight.
The paper “DESI Observations of the Andromeda Galaxy: Unraveling the Immigration History of Our Nearest Neighbor” is available for review on arXiv and will appear in The Astrophysical Journal.
