The Kraken, Released Billions of Years Ago, Collided with Milky Way
c0lo writes:
The first complete family tree of our home galaxy has been reconstructed by an international team of astrophysicists. They used artificial intelligence to decipher the movements of the 150 globular clusters that orbit the Milky Way.
In doing so they're uncovered a massive collision billions of years ago between our galaxy and what they've dubbed the "Kraken" galaxy, an event that added millions of stars to the Milky Way.
It's thought that globular clusters-dense clumps of stars older than most in the Milky Way and related to each other-are the leftovers of galaxies that merged to form our galaxy. Scientists have known for some time that galaxies can grow by the merging of smaller galaxies, but until now little has been known about how the Milky Way came to be.
[...] Using globular clusters as "fossils" to reconstruct the early assembly histories of galaxies, the researchers developed an AI suite of advanced computer simulations called E-MOSAICS that show how globular clusters form, evolve, and are destroyed.
"The main challenge of connecting the properties of globular clusters to the merger history of their host galaxy has always been that galaxy assembly is an extremely messy process, during which the orbits of the globular clusters are completely reshuffled," said Dr Diederik Kruijssen at the Center for Astronomy at the University of Heidelberg (ZAH) in Germany.
Cue a new an artificial neural network. "We tested the algorithm tens of thousands of times on the simulations and we were amazed at how accurately it was able to reconstruct the merger histories of the simulated galaxies, using only their globular cluster populations," said Kruijssen.
Here's the simulation of the mergers with globular clusters that shaped the Milky Way of today.
Ah, yes, TFSA is available in full: https://doi.org/10.1093/mnras/staa2452
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