Constraints of the Clumpyness of Dark Matter Halos Through Heating of the Disk Galaxies

Abstract

Motivated by the presence of numerous dark matter clumps in the Milky Way's halo as expected from the cold dark matter cosmological model, we conduct numerical simulations to examine the heating of the disk. We construct an initial galaxy model in equilibrium, with a stable thin disk. The disk interacts with dark matter clumps for about 5 Gyr. Three physical effects are examined : first the mass spectrum of the dark matter clumps, second the initial thickness of the galactic disk, and third the spatial distribution of the clumps. We find that the massive end of the mass spectrum determines the amount of disk heating. Thicker disks suffer less heating. There is a certain thickness at which the heating owing to the interaction with the clumps becomes saturates. We also find that the heating produced by the model which mimics the distribution found in Standard CDM cosmology is significant and too high to explain the observational constraints. On the other hand, our model that corresponds to the clump distribution in a $\Lambda$CDM cosmology produces no significant heating. This result suggests that the $\Lambda$CDM cosmology is preferable with respect to the Standard CDM cosmology in explaining the thickness of the Milky Way.

28 pages, 13 figures, submitted to ApJ

References in corpus (3)

• Probing Dark Matter Substructure in Lens Galaxies
• Halo Substructure and Disk Heating in a Lambda CDM Universe
• Contribution of the Large Magellanic Cloud to the Galactic Warp

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• The Kinematics of Thick Disks in External Galaxies
• The effect of bars and transient spirals on the vertical heating in disk galaxies
• Dynamical Effects of CDM Subhalos on a Galactic Disk
• Impact of cosmological satellites on the vertical heating of the Milky Way disc
• Thick-disk evolution induced by the growth of an embedded thin disk
• Dark matter electron anisotropy: a universal upper limit
• Simulating Sinking Satellites with SUPERBOX-10
• Satellite survival in cold dark matter cosmology
• Dwarf Galaxy Clustering and Missing Satellites
• Bar instability and formation timescale across Toomre's $Q$ parameter and central mass concentration: slow bar formation or true stability
• Semi-Analytic Modeling of Dark Matter Subhalo Encounters with Thin Stellar Streams: Statistical Predictions for GD-1-like Streams in CDM
• On the Size Evolution of a Galactic Disk in Hierarchical Merging of Cold Dark Matter Halos