2025/10/17 by Mohamamd Mazhari, Mazhari, Mohamamd
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Theory (hep-th) #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.2510.15549
openalex publication_date 2025/10/17 · openalex created_date 2025/10/21 · openalex updated_date 2026/07/28
In this work, we have constructed anisotropic bosonic dark-matter star (DMS) solutions in the context of a regularized four-dimensional Einstein-Gauss-Bonnet (4D EGB) gravity theory. Using dimensional regularization, we solve modified Tolman-Oppenheimer-Volkoff equations for a self-interacting complex scalar field in the dilute polytropic regime, pr = K ρ2, with anisotropy parameterized as σ= β pr ( 1 - e-2λ ). We perform a comprehensive numerical analysis across the \((α,β)\) parameter domain, where \(α∈ [0,8]~km2\) and \(β∈ [-2,0]\), to examine mass-radius relations and evaluate multiple stability indicators including static equilibrium \(dM/dpc\), sound-speed causality, the radial adiabatic index \(Γr\), and energy conditions. Positive Gauss-Bonnet coupling enhances both the maximum mass and compactness (e.g., \(M\rm max ≈ 1.62 M_\odot\) at \(α=0\) rising to \(≈ 2.09 M_\odot\) at \(α= 8~km2\)), while negative anisotropy reduces them (e.g., from \(≈ 2.21 M_\odot\) at \(β=0\) to \(≈ 1.73 M_\odot\) at \(β= -2\)). The resulting configurations remain statically stable up to the mass peak and satisfy physical criteria. This work extends previous isotropic boson-star analyses by systematically incorporating anisotropy within a regularized 4D EGB framework. These findings provide observationally relevant predictions for compact dark-matter objects under modified gravity.