Galaxy found to be cannibalising stars from galactic neighbours

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Researchers have discovered a dominant galaxy cannibalising on stars of its near galactic neighbours – an act that may explain how galaxies such as the Milky Way were formed.

Discovered using a highly sensitive instrument on one of the world’s largest telescopes, the galaxy’s appetite for other stars was visible after astronomers took extremely wide-view, long exposures of a nearby group of galaxies known as the M81 Group, which lies 11.7 million light years from the Milky Way.

Researchers including those from University of Edinburgh observed that the dominant galaxy – M81 – capturing stars from its two nearest neighbouring galaxies. The gravitation pull of M81 was shown to distort the shapes of the other galaxies, pulling their stars into long tails, in a process called tidal stripping.

This is for the first time that astronomers have managed to capture images of stars from smaller galaxies being ingested into M81. Researcher believe that M81 will eventually devour the smaller galaxies entirely.

Though the researchers were not surprise with the process, they didn’t expect this degree of interaction between neighbouring galaxies.

Findings from the study add to two decades of research during which evidence for this process has been mounting.
In the early 1990s, scientists discovered that our own Milky Way is in the process of subsuming a smaller system known as the Sagittarius dwarf galaxy.

The study, to be published in Astrophysical Journal Letters, was conducted using the Hyper Suprime-Cam on the Subaru Telescope in Hawaii. It was carried out by astronomers from Shanghai Astronomical Observatory, the National Astronomical Observatory of Japan, the Universities of Edinburgh and Cambridge, and Hiroshima University.