Novel Challenges in Tracking Self-Interacting Dark Matter Subhalos

Fuente: arXiv
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Autori principali: Kong, Demao, Yu, Hai-Bo, Nadler, Ethan O., Mansfield, Philip, Benson, Andrew
Natura: Preprint
Pubblicazione: 2025
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author Kong, Demao
Yu, Hai-Bo
Nadler, Ethan O.
Mansfield, Philip
Benson, Andrew
author_facet Kong, Demao
Yu, Hai-Bo
Nadler, Ethan O.
Mansfield, Philip
Benson, Andrew
contents Cosmological N-body simulations are among the primary tools for studying structure formation in the Universe. Analyses of these simulations critically depend on accurately identifying and tracking dark matter subhalos over time. In recent years, several new algorithms have been developed to improve the accuracy and consistency of subhalo tracking in cold dark matter simulations. These algorithms should be revisited in the context of new physics beyond gravity, which can modify the evolution and final properties of subhalo populations. In this work, we apply the particle-tracking-based subhalo finder Symfind to velocity-dependent self-interacting dark matter simulations with large cross section amplitudes to assess the performance of particle-tracking methods beyond the CDM paradigm. We find that the core-particle-tracking technique, which is key to the success of these algorithms in CDM, does not always yield accurate results in SIDM. The interplay between dark matter self-interactions and tidal stripping can cause the diffusion of core particles to larger radii, leading particle-tracking-based algorithms to prematurely lose track of SIDM subhalos. For massive core-expansion subhalos and core-collapse subhalos that experience close or repeated pericentric passages, a significant fraction of core particles can be lost, and particle-tracking-based finders such as Symfind offer no clear advantage over traditional methods that rely on identifying phase-space overdensities. On the other hand, for subhalos with large pericentric distances or fewer, more distant passages, Symfind tends to outperform. These differences depend sensitively on the cross section amplitude and turnover velocity of the underlying SIDM model. We therefore recommend a hybrid approach that leverages the strengths of both techniques to produce complete and robust catalogs of core-expansion and core-collapse SIDM subhalos.
format Preprint
id arxiv_https___arxiv_org_abs_2507_09799
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Novel Challenges in Tracking Self-Interacting Dark Matter Subhalos
Kong, Demao
Yu, Hai-Bo
Nadler, Ethan O.
Mansfield, Philip
Benson, Andrew
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
High Energy Physics - Phenomenology
Cosmological N-body simulations are among the primary tools for studying structure formation in the Universe. Analyses of these simulations critically depend on accurately identifying and tracking dark matter subhalos over time. In recent years, several new algorithms have been developed to improve the accuracy and consistency of subhalo tracking in cold dark matter simulations. These algorithms should be revisited in the context of new physics beyond gravity, which can modify the evolution and final properties of subhalo populations. In this work, we apply the particle-tracking-based subhalo finder Symfind to velocity-dependent self-interacting dark matter simulations with large cross section amplitudes to assess the performance of particle-tracking methods beyond the CDM paradigm. We find that the core-particle-tracking technique, which is key to the success of these algorithms in CDM, does not always yield accurate results in SIDM. The interplay between dark matter self-interactions and tidal stripping can cause the diffusion of core particles to larger radii, leading particle-tracking-based algorithms to prematurely lose track of SIDM subhalos. For massive core-expansion subhalos and core-collapse subhalos that experience close or repeated pericentric passages, a significant fraction of core particles can be lost, and particle-tracking-based finders such as Symfind offer no clear advantage over traditional methods that rely on identifying phase-space overdensities. On the other hand, for subhalos with large pericentric distances or fewer, more distant passages, Symfind tends to outperform. These differences depend sensitively on the cross section amplitude and turnover velocity of the underlying SIDM model. We therefore recommend a hybrid approach that leverages the strengths of both techniques to produce complete and robust catalogs of core-expansion and core-collapse SIDM subhalos.
title Novel Challenges in Tracking Self-Interacting Dark Matter Subhalos
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2507.09799