CNN Indonesia
Tuesday, 14 Feb 2023 17:40 WIB
The migration of stars that occurred in the Andromeda galaxy was observed by experts. (KPNO/NOIRLab/AURA/NSF/E. Slawik/D. de Martin/M. Zamani)
Jakarta, CNNIndonesia —
A number of astronomers discovered stars who apparently had immigrated to galaxy other. How will they find it?
Astronomers discovered this fact through observations using the Dark Energy Spectroscopic Instrument (DESI). Launch ScienceAlertDESI was created to measure the effects of dark energy resulting from the expansion of the Universe.
DESI measures it by collecting the optical spectral of tens of millions of objects, mostly galaxies and quasars. Then, DESI constructs a three-dimensional map as a result.
Using this method, astronomers discovered 7,000 stars in the Andromeda galaxy (M31), which is a close neighbor of the Milky Way galaxy. The stars merged into the galaxy about two billion years ago.
“Our observations of the Milky Way’s closest neighbor, the Andromeda galaxy, reveal evidence of migrating galaxies in stunning detail,” said NSF NOIRLab astronomer Arjun Dey as quoted from the official website. NOIRLab.
“Although the night sky may appear unchanged, the Universe is a dynamic thing. Galaxies like M31 and the Milky Way were composed of blocks of smaller galaxies throughout cosmic history,” he added.
According to DESI observations, about two billion years ago, a galaxy merged with Andromeda. The positions and movements of the 7,500 stars measured by DESI suggest they came from that other galaxy.
Star immigration does not only occur in the Andromeda galaxy. The Milky Way galaxy is thought to have experienced the same thing about 8 or 10 billion years ago.
Most of the stars in this galaxy came from other galaxies and merged with the Milky Way as a result of ancient mergers.
Astronomers can learn more about the ancient history of the Milky Way by closely observing the merger that occurred in the Andromeda galaxy.
“We’ve never seen this clearly before in terms of the movement of the stars. Now, we can see the results of this merger,” said University of Edinburgh astrophysicist Sergey Koposov who was also involved in the study.
“The visible photo shows that the history of the Andromeda galaxy is similar to ours, the Milky Way. The inner circumference of both galaxies is dominated by a single immigration event,” he said again.
Furthermore, this immigration finding demonstrates the power of DESI as a reliable instrument. The DESI is by far the most powerful spectrograph instrument capable of reconfiguring its five thousand separate focal planes in just two minutes.
DESI is also designed to take spectral measurements of more than 40 billion distant galaxies and quasars to map the gigantic structure of the Universe and how dark energy is driving that expansion.
“This is impossible for any other facility in the world. DESI’s extraordinary efficiency, data processing, and monitoring fields make it the best system in the world for surveying stars in the Andromeda galaxy,” said Dey.
“Within just a few hours of observation, DESI can go through more than a decade of strethoscopy with a larger telescope,” he said.
(lth/arh)
