Star-eating galaxy reveals how Milky Way was formed
The insatiable appetite of a spiral galaxy brings us a step closer in understanding how our galaxy was made
Pseudo-colour images from the Hyper Suprime-Cam prime-focus camera on the Subaru Telescope, which contains Messier 81 (centre), Messier 82 (top), and NGC 3077 (eight o’clock position on the edge of frame). Image Credit: NAOJ/HSC Project
The insatiable appetite of a spiral galaxy, which is located in a nearby group of galaxies just 12 million light years away, brings us a step closer in unravelling the mystery behind how the Milky Way was made.
Messier 81, also known as Bode’s Galaxy and of which can be found in the constellation of Ursa Major, was observed chomping down on its neighbouring galaxies’ stars. Employing the highly sensitive Hyper-Suprime-Cam on the Subaru Telescope in Hawaii, an international team of astronomers from the United Kingdom and Japan were able to see the dominant spiral galaxy’s gravitational pull truly at work since the galactic structures around it appear distorted, with their stars stretched into long tails – a process called tidal stripping.
The images from the Hawaiian telescope have revealed how stars from smaller galaxies are ingested by Messier 81 and it is expected that eventually the smaller galaxies will be devoured entirely.
Tidal stripping in galaxies. Image Credit: NASA
While the team of astronomers were not surprised to see the process taking place, the degree of interaction that they were able to witness surpassed their expectations. The findings have provided extra strong evidence for the process where some galaxies consume others – it was back in the 1990s that scientists discovered that our very own Milky Way getting stuck in to stripping its smaller companion, the Sagittarius Dwarf Galaxy.
The University of Edinburgh’s Annette Ferguson, who was part of the research, says: “The extremely faint outer regions of galaxies are challenging to study, but our findings reveal that they contain a wealth of information about how galaxies capture and cannibalise their smaller neighbours. This is important for understanding how large galaxies like our Milky Way have formed and evolved over time.”
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