The Formation of Planes of Satellite Galaxies: New Horizons Simulation
Written on January 31st , 2022 by Janvi Madhani
Cover Image Credit: Horizon AGN simulation, Dubois et al. 2014
Numerous observations in recent years have shown that the satellite galaxies orbiting our local galaxies tend to align their orbits in one or two thin planes around the host galaxy. This has been observed in local galaxies, Andromeda and Centaurus A, and our own Milky Way. Numerical simulations in a cosmological context find these planes to be rare or short-lived leading to tension between observation and theory. This leads to considerable debate on whether observations are compatible with the standard, Lambda Cold Dark Matter, model of cosmology. We argue that on large scales, these simulations did not sufficiently resolve the nearby large-scale structure, cosmic filaments, which we believe to be responsible for the anisotropic infall of satellites forming planar alignments, and on smaller scales, they did not sufficiently resolve dwarf satellite galaxies. We use the high precision, hydrodynamic, cosmological zoom simulation, New Horizon, which has both the large volume, (16 Mpc)3 and the small-scale resolution, ~ 35 pc, required to study the interplay between cosmic web dynamics and the formation, funneling, and eventually the anisotropic distribution of satellites around local galaxies. Our preliminary results indicate that these planes exist in New Horizon in ~ 30% of Milky Way-type systems. Their dynamic and kinematic coherence as well as their correlation with motions down cosmic filaments remains to be investigated. We plan to publish our results by the end of this summer, so stay tuned!
I work with Co-Investigators Dr. Charlotte Welker, Dr. Susan Kassin, and Angela Wroblewski on this project.
A movie of the formation of the large scale structure, the cosmic web, as gas cools and collapses into filaments over cosmic time in New Horizon (Dubois et al. 2020).
Recently, Charlotte and I were given the wonderful opportunity to present our results at the AAS meeting in Pasadena in a press conference! You can listen to our talk here, starting at 18:30!
Pictured left to right: Katya Gozman, Eric Bell, Janvi Madhani, Charlotte Welker, and Hollis Akins. (Photo Credit: AAS Press)
