Bayesian Constraints on Bosonic Dark Matter in Neutron Stars within a Covariant Density-Functional Equation-of-State Ensemble
Abstract
We investigate neutron stars admixed with repulsively self-interacting bosonic dark matter (DM) using current multi-messenger observations. The dark component is modeled as a complex scalar field coupled to baryonic matter only through gravity, allowing dark-core and dark-halo configurations. To quantify baryonic equation-of-state (EOS) uncertainties, we combine a three-dimensional scan over (mχ,λ,Fχ) with 27 DDME2-based covariant density-functional EOSs spanning Lsym=30,50,70 MeV and −600≤ Qsat≤ 1000 MeV. The models are confronted in a Bayesian framework with NICER mass--radius measurements from the Amsterdam and Maryland/Illinois analyses and the GW170817 tidal-deformability constraint. After Bayesian evidence weighting over the EOS ensemble, the EOS-relevant dark-sector scale μχ≡ mχ/λ1/4 is localized around 250 MeV for both NICER data sets. In the (mχ,λ) parameterization, the marginalized boson-mass posterior peaks at mχ≃300--$330$ MeV, while λ remains broadly distributed. Since the bosonic EOS depends on mχ and λ only through μχ, their separate marginals are conditional on the adopted independent priors. The inferred DM fraction is more data-set dependent, with posterior modes near 4% for Maryland/Illinois and 12% for Amsterdam. Bosonic DM also shifts the inferred Qsat from negative toward intermediate and positive values, whereas the response of Lsym is weaker. This indicates a model-dependent trade-off between DM-induced compactification and the high-density stiffness of baryonic matter. These constraints remain conditional on the selected EOS family and the assumption of a common effective Fχ for all sources.
Related
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BibTeX
@misc{karkevandi2026bayesian,
title = {{Bayesian Constraints on Bosonic Dark Matter in Neutron Stars within a Covariant Density-Functional Equation-of-State Ensemble}},
author = {Davood Rafiei Karkevandi and Alexander Ayriyan and Armen Sedrakian},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.38055},
eprint = {2609.38055},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.38055},
}
RIS
TY - UNPB
TI - Bayesian Constraints on Bosonic Dark Matter in Neutron Stars within a Covariant Density-Functional Equation-of-State Ensemble
AU - Davood Rafiei Karkevandi
AU - Alexander Ayriyan
AU - Armen Sedrakian
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.38055
UR - https://arxiv.org/abs/2609.38055
AB - We investigate neutron stars admixed with repulsively self-interacting bosonic dark matter (DM) using current multi-messenger observations. The dark component is modeled as a complex scalar field coupled to baryonic matter only through gravity, allowing dark-core and dark-halo configurations. To quantify baryonic equation-of-state (EOS) uncertainties, we combine a three-dimensional scan over (m_χ,λ,F_χ) with 27 DDME2-based covariant density-functional EOSs spanning L_sym=30,50,70 MeV and −600≤ Q_sat≤ 1000 MeV. The models are confronted in a Bayesian framework with NICER mass--radius measurements from the Amsterdam and Maryland/Illinois analyses and the GW170817 tidal-deformability constraint. After Bayesian evidence weighting over the EOS ensemble, the EOS-relevant dark-sector scale μ_χ≡ m_χ/λ^1/4 is localized around 250 MeV for both NICER data sets. In the (m_χ,λ) parameterization, the marginalized boson-mass posterior peaks at m_χ≃300--$330$ MeV, while λ remains broadly distributed. Since the bosonic EOS depends on m_χ and λ only through μ_χ, their separate marginals are conditional on the adopted independent priors. The inferred DM fraction is more data-set dependent, with posterior modes near 4% for Maryland/Illinois and 12% for Amsterdam. Bosonic DM also shifts the inferred Q_sat from negative toward intermediate and positive values, whereas the response of L_sym is weaker. This indicates a model-dependent trade-off between DM-induced compactification and the high-density stiffness of baryonic matter. These constraints remain conditional on the selected EOS family and the assumption of a common effective F_χ for all sources.
ER -