Dark matter distributions around extreme mass ratio inspirals: effects of radial pressure and relativistic treatment

We investigate different treatments of dark matter (DM) distributions surrounding extreme mass ratio inspirals (EMRIs) to assess their impact on orbital evolution and gravitational wave emission. Density profiles derived from the mass current and from the energy-momentum tensor using a distribution function yield consistent results, but both differ substantially from profiles obtained using an anisotropic fluid model based on Einstein cluster ansatz. We find that the inclusion of radial pressure significantly modifies both the orbital dynamics and the resulting gravitational wave waveforms. By analyzing waveform dephasing and mismatches, we show that a fully relativistic treatment of DM distributions can substantially alter the detectability thresholds of DM halos. Our results demonstrate that radial pressure and relativistic modeling of DM are essential for accurately describing the dynamics and observational signatures of EMRIs embedded in DM halos.

💡 Research Summary

This paper presents a comprehensive relativistic analysis of dark‑matter (DM) halos surrounding extreme‑mass‑ratio inspirals (EMRIs) and investigates how the inclusion of radial pressure influences orbital dynamics and gravitational‑wave (GW) signals. The authors begin by modeling a Hernquist‑type DM halo using the Newtonian density profile ρ₀(r)=M a₀²/