Nav: Home

New evidence shows crash with Antlia 2 gave the Milky Way the ripples in its outer disc

June 12, 2019

The newly-discovered dark dwarf galaxy Antlia 2's collision with the Milky Way may be responsible for our galaxy's characteristic ripples in its outer disc, according to a study led by Rochester Institute of Technology Assistant Professor Sukanya Chakrabarti.

The Antlia 2 dwarf galaxy was discovered from the second data release of the European Space Agency's Gaia mission, which aims to chart a three-dimensional map of our galaxy. Antlia 2's current location closely matches the location of a dark-matter dominated dwarf galaxy that Chakrabarti predicted in 2009 through a dynamical analysis. Using the Gaia data, Chakrabarti 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 the outer gas disc of our galaxy.

Upcoming additional data releases from Gaia will provide further clarity, and Chakrabarti said that she and her team have made "a hand-on-the-cutting-board kind of prediction of what to expect for the motion of the stars in the Antlia 2 dwarf galaxy in future Gaia data releases." Chakrabarti said the discovery could help develop methods to hunt for dark galaxies and ultimately solve the long-standing puzzle of what dark matter is.

"We don't understand what the nature of the dark matter particle is, but if you believe you know how much dark matter there is, then what's left undetermined is the variation of density with radius," said Chakrabarti. "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."

The researchers also explored other potential causes for the ripples in the Milky Way's outer disc, 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.

Chakrabarti presented her findings at the 234th meeting of the American Astronomical Society in St. Louis, Mo., on Wednesday, June 12.
-end-
Chakrabarti's work is supported by NASA ATP NNX17AK90G and NSF AAG grant 1517488. Other researchers contributing to the study included Philip Chang, associate professor at University of Wisconsin-Milkwaukee; Adrian Price-Whelan, postdoctoral fellow at Princeton University; Justin Read, professor at University of Surrey; Leo Blitz, professor at University of California Berkeley; and Lars Hernquist, professor at Harvard University.

For more information, contact Luke Auburn at 585-475-4335 or luke.auburn@rit.edu.

Rochester Institute of Technology

Related Dark Matter Articles:

Does dark matter annihilate quicker in the Milky Way?
Researchers at the Tata Institute of Fundamental Research in Mumbai have proposed a theory that predicts how dark matter may be annihilating much more rapidly in the Milky Way, than in smaller or larger galaxies and the early Universe.
Origin of Milky Way's hypothetical dark matter signal may not be so dark
A mysterious gamma-ray glow at the center of the Milky Way is most likely caused by pulsars.
A new look at the nature of dark matter
A new study suggests that the gravitational waves detected by the LIGO experiment must have come from black holes generated during the collapse of stars, and not in the earliest phases of the Universe.
Dark matter may be smoother than expected
Analysis of a giant new galaxy survey, made with ESO's VLT Survey Telescope in Chile, suggests that dark matter may be less dense and more smoothly distributed throughout space than previously thought.
Supercomputer comes up with a profile of dark matter
In the search for the mysterious dark matter, physicists have used elaborate computer calculations to come up with an outline of the particles of this unknown form of matter.
Mapping the 'dark matter' of human DNA
Researchers from ERIBA, Radboud UMC, XJTU, Saarland University, CWI and UMC Utrecht have made a big step towards a better understanding of the human genome.
Reconciling dwarf galaxies with dark matter
Dwarf galaxies are enigmas wrapped in riddles. Although they are the smallest galaxies, they represent some of the biggest mysteries about our universe.
Did gravitational wave detector find dark matter?
When an astronomical observatory detected two black holes colliding in deep space, scientists celebrated confirmation of Einstein's prediction of gravitational waves.
Dark matter does not contain certain axion-like particles
Researchers at Stockholm University are getting closer to corner light dark-matter particle models.
SDU researchers present a new model for what dark matter might be
There are indications that we might never see the universe's mysterious dark matter.

Related Dark Matter Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Climate Crisis
There's no greater threat to humanity than climate change. What can we do to stop the worst consequences? This hour, TED speakers explore how we can save our planet and whether we can do it in time. Guests include climate activist Greta Thunberg, chemical engineer Jennifer Wilcox, research scientist Sean Davis, food innovator Bruce Friedrich, and psychologist Per Espen Stoknes.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...