Creating a galaxy lacking dark matter in a dark matter-dominated universe
Abstract
We use hydrodynamical cosmological simulations to show that it is possible to create, via tidal interactions, galaxies lacking dark matter (DM) in a DM-dominated universe. We select dwarf galaxies from the NIHAO project, obtained in the standard cold dark matter model and use them as initial conditions for simulations of satellite-central interactions. After just one pericentric passage on an orbit with a strong radial component, NIHAO dwarf galaxies can lose up to 80 per cent of their DM content, but, most interestingly, their central (≈8 kpc) DM-to-stellar mass ratio changes from a value of ∼25, as expected from numerical simulations and abundance matching techniques, to roughly unity as reported for NGC 1052-DF2 and NGC 1054-DF4. The stellar velocity dispersion drops from ∼30 $\, \rm km\, s^{-1}$ before infall to values as low as 6 ± 2 $\, \rm km\, s^{-1}$ . These, and the half-light radius around 3 kpc, are in good agreement with observations from van Dokkum and collaborators. Our study shows that it is possible to create a galaxy without DM starting from typical dwarf galaxies formed in a DM-dominated universe, provided they live in a dense environment.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2021
- DOI:
- 10.1093/mnras/staa3716
- arXiv:
- arXiv:2010.02245
- Bibcode:
- 2021MNRAS.501..693M
- Keywords:
-
- methods: numerical;
- galaxies: formation;
- galaxies: kinematics and dynamics;
- dark matter;
- cosmology: theory;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 8 pages, 11 figures. Two extra figures added, accepted for publication in MNRAS