Scientists have detected the smallest intergalactic cannibalism
One of the dwarf satellite galaxies of the milky Way through the intergalactic collision billions of years ago.
According to a new study published in the journal Monthly Notices of the Royal Astronomical Society, two astronomers from the Canary Institute of astrophysics and University of La Laguna discovered probably the smallest case of galactic cannibalism. Moreover, apparently, it happened near the Milky Way – one of the dwarf spheroidal satellite galaxies.
This dwarf galaxy is about 12 billion years. It is about 100 thousand times smaller than solar mass than in the milky Way. The authors suggest that it has reached such proportions only after he had consumed his neighbor even smaller.
The researchers analyzed data from several previous studies to compare different colors, brightness and the orbital velocity of stars Sextants. They found several interesting patterns. It turned out, the Sextants have blue stars with a low metal content and red with a high content of metals, in addition, the behavior of these two groups varies greatly. Whereas the blue stars were arranged in round clusters, the Reds were scattered and more erratic elliptical orbit.
“The most reasonable explanation for this phenomenon – the merger of two galaxies with different metal properties,” explains the study’s lead author Luis Sequence.
The team also found other oddities. Data on speeds showed that the stars with low metal content formed a ring-shaped substructure in the depths of the galaxy. All the stars in this ring turned out to be less metal content than their neighbors. We also found out that they rotate around the galaxy faster than other stars.
The researchers suggested that this ring of stars with low metal content formed when a companion galaxy swallowed the neighbor with lower metal properties billions of years ago. To know for sure whether these stars are living remnants of ancient galaxies, or they were formed during the merger, and requires further investigation. But in any case scientists have found the smallest example of intergalactic cannibalism ever observed
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