• DOI:10.3847/2041-8213/aca6e5
• Corpus ID: 245853725

New Constraints on the Dark Matter Density Profiles of Dwarf Galaxies from Proper Motions of Globular Cluster Streams

@article{Malhan2022NewCO,
  title={New Constraints on the Dark Matter Density Profiles of Dwarf Galaxies from Proper Motions of Globular Cluster Streams},
  author={Khyati Malhan and Monica Valluri and Katherine Freese and Rodrigo A. Ibata},
  journal={The Astrophysical Journal Letters},
  year={2022},
  volume={941}
}

• K. Malhan, M. Valluri, +1 author R. Ibata
• Published 10 January 2022
• Physics
• The Astrophysical Journal Letters

The central density profiles in dwarf galaxy halos depend strongly on the nature of dark matter (DM). Recently, in Malhan et al. we employed N-body simulations to show that the cuspy cold DM subhalos predicted by cosmological simulations can be differentiated from cored subhalos using the properties of accreted globular cluster (GC) streams since these GCs experience tidal stripping within their parent halos prior to accretion onto the Milky Way. We previously found that clusters that are accreted within cuspy subhalos produce streams with larger physical widths and higher dispersions in line-of-sight velocity and angular momentum than streams that are accreted within cored subhalos. Here, we use the same suite of simulations to demonstrate that the dispersion in the tangential velocities of streams ( σvTan ) is also sensitive to the central DM density profiles of their parent dwarfs and GCs that they were accreted from; cuspy subhalos produce streams with larger σvTan than those accreted inside cored subhalos. Using Gaia EDR3 observations of multiple GC streams we compare their σvTan values with simulations. The measured σvTan values are consistent with both an “in situ” origin and with accretion inside cored subhalos of M ∼ 108–9 M ⊙ (or very low-mass cuspy subhalos of mass ∼108 M ⊙). Despite the large current uncertainties in σvTan , we find a low probability that any of the progenitor GCs were accreted from cuspy subhalos of M ≳ 10 9 M ⊙. The uncertainties on Gaia tangential velocity measurements are expected to decrease in future and will allow for stronger constraints on subhalo DM density profiles.