Mixed dark matter models for the peculiar compact object in remnant HESS J1731-347 and their implications for gravitational wave properties

A recent assessment of the central compact object in the supernova remnant HESS J1731 - 347 [Nat. Astron. 6, 1444 (2022)] reveals its remarkably small radius, accompanied by the intriguing characteristic of a mass smaller than one solar mass, a feature that has hitherto defied a conclusive explanation. To explain the astrophysical features of this peculiar source, in the present work, we consider two distinct dark matter models: the single-fluid dark matter model and the two-fluid dark matter model, both mixed within neutron stars. These two models can meet various astronomical observational constraints well and successfully account for the observational requirements of HESS J1731 - 347. We further estimate the parameter space of these two dark matter classes in light of multimessenger observational constraints. Additionally, we investigate the effects of these dark matter models on tidal deformability, neutron star nonradial oscillation frequencies, and gravitational waves during the binary neutron star inspiral process. Our findings underscore the pivotal role played by dark matter in shaping the gravitational wave-related properties of neutron stars, thereby offering valuable insights for future observations.