The Effect of Adiabatic Compression on Dark Matter Halos and the Radial Acceleration Relation

Authors

Pengfei Li, Case Western Reserve UniversityFollow
Stacy S. McGaugh, Case Western Reserve UniversityFollow

Author ORCID Identifier

Stacy S. McGaugh

Document Type

Article

Publication Date

3-17-2022

Abstract

We use a semiempirical model to investigate the radial acceleration relation (RAR) in a cold dark matter (CDM) framework. Specifically, we build 80 model galaxies covering the same parameter space as the observed galaxies in the SPARC database, assigning them to dark matter (DM) halos using abundance-matching and halo mass-concentration relations. We consider several abundance-matching relations, finding some to be a better match to the kinematic data than others. We compute the unavoidable gravitational interactions between baryons and their DM halos, leading to an overall compression of the original Navarro-Frenk-White (NFW) halos. Before halo compression, high-mass galaxies lie approximately on the observed RAR, whereas low-mass galaxies display up-bending "hooks"at small radii due to DM cusps, making them deviate systematically from the observed relation. After halo compression, the initial NFW halos become more concentrated at small radii, making larger contributions to rotation curves. This increases the total accelerations, moving all model galaxies away from the observed relation. These systematic deviations suggest that the CDM model with abundance matching alone cannot explain the observed RAR. Further effects (e.g., feedback) would need to counteract the compression with precisely the right amount of halo expansion, even in high-mass galaxies with deep potential wells where such effects are generally predicted to be negligible.

Publication Title

Astrophysical Journal

Grant

80NSSC19k0570

Rights

© 2022. The Author(s). Published by the American Astronomical Society. This is an Open Access work distributed under the terms of the Creative Commons Attribution Licence (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Pengfei Li et al. The Effect of Adiabatic Compression on Dark Matter Halos and the Radial Acceleration Relation. 2022 ApJ 927 198