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Disruption of Dark Matter Minihaloes in the Milky Way environment: Implications for Axion Miniclusters and Early Matter Domination

Shen, Xuejian and Xiao, Huangyu and Hopkins, Philip F. and Zurek, Kathryn M. (2022) Disruption of Dark Matter Minihaloes in the Milky Way environment: Implications for Axion Miniclusters and Early Matter Domination. . (Unpublished)

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Many theories of dark matter beyond the Weakly Interacting Massive Particles (WIMP) paradigm feature an enhanced matter power spectrum on sub-parsec scales, leading to the formation of dense dark matter minihaloes. While these minihaloes are currently weakly constrained, future local observations, through a variety of techniques, may strongly constrain such substructures. The survival probability of those dense minihaloes in the Milky Way environment is crucial for interpreting local observations. In this work, we investigate two disruption effects: stellar disruption and (smooth) tidal disruption. These two mechanisms are studied using semi-analytic models and idealized N-body simulations. For stellar disruption, we perform a series of N-body simulations of isolated minihalo-star encounters to test and calibrate analytic models of stellar encounters, and apply the model to the realistic Milky Way disk environment. For tidal disruption, we also perform N-body simulations to confirm the effectiveness of the analytic treatment. Finally, we propose a framework to combine the stellar and tidal disruption of minihaloes with an orbit model, using it to make predictions for the overall survival probability of minihaloes in the Milky Way. We find the survival fraction for dense dark matter minihaloes, e.g. for axion miniclusters and minihaloes from Early Matter Domination, is ∼70%, with the relatively low-mass, compact population surviving. The survival fraction is insensitive to the detailed model parameters. We discuss various implications for their mass functions and future detection prospects.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper ItemCode
Shen, Xuejian0000-0002-6196-823X
Xiao, Huangyu0000-0003-2485-5700
Hopkins, Philip F.0000-0003-3729-1684
Zurek, Kathryn M.0000-0002-2629-337X
Additional Information:We thank Andrea Mitridate for useful discussions on the mass-concentration relation and Gabriel Aguiar for the collaboration in the early stages of this work. HX is supported in part by the United States Department of Energy (DOE) under grant number DE-SC0011637. Support for XS and PFH was provided by the National Science Foundation (NSF) Research Grants 1911233, 20009234, 2108318, NSF CAREER grant 1455342, the National Aeronautics and Space Administration (NASA) grants 80NSSC18K0562, HST-AR-15800. Numerical calculations were run on the Caltech computing cluster “Wheeler”, allocations AST21010 and AST20016 supported by the NSF and the Texas Advanced Computing Center (TACC), and NASA HEC SMD-16-7592. DATA AVAILABILITY. The simulation data of this work was generated and stored on the computing system “Wheeler” at California Institute of Technology. The code for the semi-analytic model and the summary of simulation results are available at project repository. The raw data of the idealized simulations will be shared on reasonable request to the corresponding author.
Group:TAPIR, Walter Burke Institute for Theoretical Physics
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0011637
Texas Advanced Computing Center (TACC)UNSPECIFIED
Subject Keywords:dark matter – cosmology: miscellaneous – methods: numerical – Galaxy: kinematics and dynamics – solar neighbourhood
Record Number:CaltechAUTHORS:20220816-192431512
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:116317
Deposited By: George Porter
Deposited On:16 Aug 2022 22:52
Last Modified:02 Jun 2023 01:28

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