Enhanced Disruption of Axion Minihalos by Multiple Stellar Encounters in the Milky Way

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Auteurs principaux: DSouza, Ian, Gordon, Chris, Forbes, John C.
Format: Preprint
Publié: 2024
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author DSouza, Ian
Gordon, Chris
Forbes, John C.
author_facet DSouza, Ian
Gordon, Chris
Forbes, John C.
contents If QCD axion dark matter formed post-inflation, axion miniclusters emerged from isocurvature fluctuations and later merged hierarchically into minihalos. These minihalos, potentially disrupted by stellar encounters in the Milky Way, affect axion detectability. We extend prior analyses by more accurately incorporating multiple stellar encounters and dynamical relaxation timescales, simulating minihalo orbits in the Galactic potential. Our results show stellar interactions are more destructive than previously estimated, reducing minihalo mass retention at the solar system to ~30%, compared to earlier estimates of ~60%. This enhanced loss arises from cumulative energy injections when relaxation periods between stellar encounters are accounted for. The altered minihalo mass function implies a larger fraction of axion dark matter occupies inter-minihalo space, potentially increasing the local axion density and improving haloscope detection prospects. This work highlights the significance of detailed modeling of stellar disruptions in shaping the axion dark matter distribution.
format Preprint
id arxiv_https___arxiv_org_abs_2411_16166
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Enhanced Disruption of Axion Minihalos by Multiple Stellar Encounters in the Milky Way
DSouza, Ian
Gordon, Chris
Forbes, John C.
Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
If QCD axion dark matter formed post-inflation, axion miniclusters emerged from isocurvature fluctuations and later merged hierarchically into minihalos. These minihalos, potentially disrupted by stellar encounters in the Milky Way, affect axion detectability. We extend prior analyses by more accurately incorporating multiple stellar encounters and dynamical relaxation timescales, simulating minihalo orbits in the Galactic potential. Our results show stellar interactions are more destructive than previously estimated, reducing minihalo mass retention at the solar system to ~30%, compared to earlier estimates of ~60%. This enhanced loss arises from cumulative energy injections when relaxation periods between stellar encounters are accounted for. The altered minihalo mass function implies a larger fraction of axion dark matter occupies inter-minihalo space, potentially increasing the local axion density and improving haloscope detection prospects. This work highlights the significance of detailed modeling of stellar disruptions in shaping the axion dark matter distribution.
title Enhanced Disruption of Axion Minihalos by Multiple Stellar Encounters in the Milky Way
topic Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2411.16166