The new map reveals how a nearby dwarf galaxy called the Large Magellanic Cloud sailed through the Milky Way’s halo like a ship through water, its gravity leaving a trail on the stars in its wake.
It is the first map to provide a similar image of the outer regions of the halo, where the stela is located, some 200,000 to 325,000 light-years from the galactic center.
“Stealing energy from a smaller galaxy is not only the reason why the Large Magellanic Cloud is merging with the Milky Way, but also why all galaxy mergers occur,” says Rohan Naidu. , a graduate student at Harvard University. “The stele on our map is a very clear confirmation that our basic image of how galaxies merge is correct!”
The researchers, using data from NEOWISE and GAIA, mapped the positions of 1,301 stars in the Milky Way’s halo . First, with GAIA they obtained the location of many stars in the sky. After identifying the stars likely to be in the halo, they looked for stars that belonged to a class of giant stars that have a specific signature detectable by NEOWISE. Thus they created the new map.
“Confirming our theoretical prediction with observational data tells us that our understanding of the interaction between these two galaxies is on the right track,” clarifies Nicolás Garavito-Camargo, a doctoral student at the University of Arizona.
The new map may provide proof for different theories about the nature of dark matter, such as whether it is made up of particles, like regular matter, and what the properties of those particles are.
Reference: C. Conroy et al. 2021. All-sky dynamical response of the Galactic halo to the Large Magellanic Cloud. Nature 592: 534-536; doi: 10.1038 / s41586-021-03385-7
