With a new simulation that shows how satellite galaxies orbit bigger galaxies like the Milky Way, Johns Hopkins University researchers have reconciled long-dueling visions of what astronomers actually see using telescopes and what theorists have predicted they should see.
“When people started to see these streams of satellite galaxies everywhere in their telescopes, the modelers who run these super computer simulations said, ‘Oh! Impossible! These should be very rare at best!’” said Charlotte Welker, a post-doctoral fellow, who worked on the solution with Janvi Madhani, a second year PhD student.
They believe the problem is not actually with our cosmological model of the universe, but stems from the simulations itself because past simulations suffered from a lack of resolution on small scales and a lack of volume on large scales.
“It’s a real ah-ha moment,” said Susan Kassin, an astronomer at the Space Telescope Science Institute, who advised the team.
The team will discuss their findings at 5:15 p.m. EST June 14 with press availability at the American Astronomical Society conference, which will be livestreamed.
The Hopkins team used what they call “zoom-in simulation” to study a larger area at a higher, close-up resolution. Called New Horizon, this cosmological simulation was developed by their collaborators in Paris in 2018.
The resulting simulations showed 30 percent of Milky Way type galaxies to display planes, compared to previous studies which found planes in less than 2 percent of candidate systems.
“With this new result, we no longer have to abandon our model of cosmology or adopt a new theory of gravity to explain the occurrence of these planes,” said Madhani.
The Johns Hopkins researchers worked on their simulation with scientists from Institut d’Astrophysique de Paris and Yonsei University in Seoul. This work was supported by National Science Foundation Grant No. 1815251 and a STScI/RSAC grant.
To reach either Madhani or Welker contact lauracech@jhu.edu.
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