|Universal Multistream Radial Structures of Cold Dark Matter Halos
Taruya, Atsushi https://orcid.org/0000-0002-4016-1955 (unconfirmed)
|Galaxy dark matter halos
Large-scale structure of the universe
|American Astronomical Society
|The Astrophysical Journal Letters
|Virialized halos of cold dark matter generically exhibit multistream structures of accreted dark matter within an outermost radial caustic known as the splashback radius. By tracking the particle trajectories that accrete onto the halos in cosmological N-body simulations, we count their number of apocenter passages (p) and use them to characterize the multistream structure of dark matter particles. We find that the radial density profile for each stream, classified by the number of apocenter passages, exhibits universal features and can be described by a double power-law function comprising shallow inner slopes and steep outer slopes of indices of −1 and −8, respectively. Surprisingly, these properties hold over a wide range of halo masses. The double power-law feature is persistent when dividing the sample by concentration or accretion rate. The dependence of the characteristic scale and amplitude of the profile on p cannot be replicated by known self-similar solutions, requiring consideration of complexities such as the distribution of angular momentum or mergers.
|© 2023. The Author(s). Published by the American Astronomical Society
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
|Appears in Collections:
This item is licensed under a Creative Commons License