Last year marked the discovery of Antlia galaxy that is apparently merging with the Milky Way. We may be forgiven for not detecting the massive universal body sooner due to the fact that scientists are describing it as a sort of ghost town but just on a larger scale. This ghost galaxy is believed to have begun colliding with our own a few hundred million years ago and may be responsible for a thing or two.
New research has marked interesting ripples in the Milky Way outer disc that is formed primarily out of hydrogen gas. Curiously enough, Sukanya Chakrabarti, an astrophysicist at the Rochester Institute of Technology, had predicted that a galaxy, rich in dark matter, was in the same location Antlia 2 was discovered in 9 years later.
The second Gaia mission is responsible for discovering the merger of galaxies. Antlia 2 is a so-called satellite galaxy and it’s gargantuan, coming close to the Large Magellanic Cloud in size. The team lead by Chakrabarti has calculated the past course undertaken by Antlia 2, using new data from the Gaia mission. This simulation has confirmed the current position held by the dwarf galaxy, as well as the ripples it made in the Milky Way hundreds of million years ago.
Scientists found proof that Milky Way merged with another galaxy
Ripples that were previously believed to be made by another Milky Way satellite called the Sagittarius Dwarf Spheroidal Galaxy.
Scientists have the following comments: “If Antlia 2 is the dwarf galaxy we predicted, you know what its orbit had to be. You know it had to come close to the galactic disc. That sets stringent constraints, therefore, on not just on the mass, but also its density profile. That means that ultimately you could use Antlia 2 as a unique laboratory to learn about the nature of dark matter.
Simulations point to Anlia 2 having lost much of its matter to the Milky Way during their past interactions. In case of such collisions, the history of the dwarf galaxy could be traced. Astronomers mark that the bulk of dark matter is usually found near a galaxy’s core but Anlia 2 may well be an exception, evidenced by its dispersed build.
While still leaving room for the possibility that another event is responsible for the outer disk disturbance, scientists are awaiting new data from the next Gaia mission that will confirm their theories. This study will be published in the Astrophysical Journal and is available now on arXiv.