Extracting dark-matter velocities from halo masses: A reconstruction conjecture
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PhysRevD.106.083506.pdf
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Department of Physics, University of ArizonaIssue Date
2022
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American Physical SocietyCitation
Dienes, K. R., Huang, F., Kost, J., Manogue, K., & Thomas, B. (2022). Extracting dark-matter velocities from halo masses: A reconstruction conjecture. Physical Review D, 106(8).Journal
Physical Review DRights
Copyright © 2022 American Physical Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Increasing attention has recently focused on nontraditional dark-matter production mechanisms which result in primordial dark-matter velocity distributions with highly nonthermal shapes. In this paper, we undertake an assessment of how the detailed shape of a general dark-matter velocity distribution impacts structure formation in the nonlinear regime. In particular, we investigate the impact on the halo-mass and subhalo-mass functions, as well as on astrophysical observables such as satellite and cluster-number counts. We find that many of the standard expectations no longer hold in situations in which this velocity distribution takes a highly nontrivial, even multimodal shape. For example, we find that the nominal free-streaming scale alone becomes insufficient to characterize the effect of free-streaming on structure formation. In addition, we propose a simple one-line conjecture which can be used to "reconstruct"the primordial dark-matter velocity distribution directly from the shape of the halo-mass function. Although our conjecture is completely heuristic, we show that it successfully reproduces the salient features of the underlying dark-matter velocity distribution even for nontrivial distributions which are highly nonthermal and/or multimodal, such as might occur for nonminimal dark sectors. Moreover, since our approach relies only on the halo-mass function, our conjecture provides a method of probing dark-matter properties even for scenarios in which the dark and visible sectors interact only gravitationally. © 2022 American Physical Society. American Physical Society.Note
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2470-0010Version
Final published versionae974a485f413a2113503eed53cd6c53
10.1103/PhysRevD.106.083506