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Milky Way Collided with Dark-Matter Dominated Galaxy Less Than Billion Years Ago | Astronomy



According to new research led by Rochester Institute of Technology (RIT), the collision of the recently discovered dwarf galaxy Antlia 2 with our Milky Way Galaxy hundreds of millions of years ago is responsible for ripples in the Milky Way's outer gas disk

 The Large Magellanic Cloud, the Milky Way Galaxy and Antlia 2 (from left to right). Image credit: V. Belokurov / Marcus and Gail Davies / Robert Gendler

The Large Magellanic Cloud, the Milky Way Galaxy and Antlia 2 (from left to right). Image credit: V. Belokurov / Marcus and Gail Davies / Robert Gendler

Antlia 2 was discovered in 201

8 data from the second data release or ESA's Gaia mission

The dwarf galaxy is located in the constellation Antlia, approximately 130,000 light-years from Earth

It is as big as the Large Magellanic Cloud, and a third of the Milky Way itself.

Antlia 2's current location closely matched the location of a dark-matter dominated dwarf galaxy that astronomers predicted in 2009 through a dynamic analysis.

Using the Gaia data, they calculated its past trajectory and found that Antlia 2 would have crashed into the Milky Way and produced the large ripples that we see in its outer gas disk. 19659005] "The discovery could help develop methods for hunting for dark galaxies and ultimately solve the long-standing puzzle of what is dark matter," said RIT astrophysicist Sukanya Chakrabarti, lead author of the study. is what the nature of the dark matter particle is, but if you know how much dark matter there is, then what's left undetermined is the variation of density with radius. ”

“ 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 disk. That sets strictly constraints, therefore, 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. ”

Dr. Chakrabarti and her colleagues also explored other potential causes for the ripples in the Milky Way's outer disk, but ruled out the other candidates.

The Sagittarius dwarf galaxy's tidal strength was insufficient and the Large and Small Magellanic Clouds are too distant.

] The evidence points to Antlia 2 as the most likely cause.

"Upcoming additional data releases from Gaia will provide further clarity," Dr. Chakrabarti said.

“We made a hand-on-the-cutting board of prediction of what to expect for the motion of the stars in the Antlia 2 dwarf galaxy in future Gaia data releases.”

The team's

” src=”http://cdn.sci-news.com/images/2018/11/image_6605-Antlia-2.jpg” width=”580″ height=”283″/> ” src=”http://cdn.sci-news.com/images/2018/11/image_6605-Antlia-2.jpg” width=”580″ height=”283″/> ” src=”http://cdn.sci-news.com/images/2018/11/image_6605-Antlia-2.jpg” width=”580″ height=”283″/> ” src=”http://cdn.sci-news.com/images/2018/11/image_6605-Antlia-2.jpg” width=”580″ height=”283″/> Sukanya Chakrabarti et al. 2019. Antlia2's role in driving the ripples in the outer gas disk of the Galaxy. APJL a press; arXiv: 1906.04203


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