The Milky Way devoured another dwarf galaxy billions of years ago
Scientists have discovered that the Milky Way consumed another dwarf galaxy which collided with it long ago. A group of scientists while trying to understand how Milky Way was formed, came across signs of a collision between the two galaxies. The findings were presented in a new research paper. The paper was published in the scientific journal Nature Astronomy.
The scientists suggest that our home galaxy was able to convert the enormous amount of mass that it collected from the dwarf galaxy, which they call Gaia-Enceladus, to fuel itself for billions of years. The collision also gave way to the formation of many new stars and celestial bodies. The team of researchers took the help of the Gaia space telescope which belongs to the European Space Agency (ESA), for conducting the research.
The telescope designed for astrometry helped in measuring the exact location and motion of more than a million stars in the galaxy. Having analyzed the stars this way, the researchers were able to observe that they can be categorized into two groups. Of these, one group showed signs of having been formed due to an accretion event. The researchers took this as evidence of an intergalactic collision. Their theory was backed by the data they collected through the Gaia telescope about the age of the stars.
Carme Gallart, lead author of the research told AFP that “The novelty of our work is that we have been able to assign precise ages to the stars that belong to the galaxies that merged and, by knowing these ages, when the merger took place.” The researchers inferred that our galaxy gradually swallowed the smaller galaxy through a slow process. Scientist expects our neighboring Andromeda galaxy to one day collide with our own. However, that may take up to 4.5 billion of years.