Dark matter subhalo disturbance in the tidal field: Towards a new simulations accuracy

Abstract

Dark matter (DM) identification is a pressing challenge for modern particle physics and cosmology. The success of this endeavor, however, is contingent on a number of parameters, some of which stem from the difficulty of predicting the DM sub-halo distribution in Milky Way-like galaxies and others from the effect of DM sub-halo signals on the gamma-ray instruments being utilized. This research compared the results of detailed simulations of individual DM sub-halos emerging in the external tidal fields with and without disc components and a baryonic bulge. The average DM particle is assumed to have a mass three times smaller than that assumed in cosmological zoom-in simulations of galaxy formation. The Via Lactea II simulation, which provides the basis for simulating the sub-haloes' tidal field in DM, was used to establish the baseline conditions for this investigation. A model of the Milky Way based on observations was used to simulate the tidal field; this model included a DM halo, a stellar bulge, and a stellar disc. When small (rp 24 kpc) percenters were included, the number of sub-haloes dropped to 39%, and the remaining sub-haloes were found to have a less dense orbital distribution. Since the total number of outer sub-haloes was only around 74% of the value anticipated by CDM, the addition of a stellar component to the tidal field had little effect on the sub-haloes with greater percenters. Previous research on the impacts of baryonic matter as mediated via the spurious disruption had reported ratios that were lower than the ones obtained in this study, suggesting that the latter's accuracy was to blame.