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تسجيل مستخدم جديدConstraining Self-Interacting Dark Matter with Dwarf Spheroidal Galaxies and High-resolution Cosmological $N$-body Simulations
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We study the density structures of dark matter subhalos for both cold dark matter and self-interacting dark matter models using high-resolution cosmological $N$-body simulations. We quantify subhalos central density at 150 pc from the center of each subhalo at the classical dwarf spheroidal and ultrafaint dwarf scales. By comparing them with observations, we find that the self-interacting scattering cross-section of $sigma/m<3 rm{cm^{2}g^{-1}}$ is favored. Due to the combination of hosts tide and self-interactions, the central density of subhalos with small pericenter shows a noticeable difference between the cold and the self-interacting models, indicating that dwarf satellites with small pericenter are ideal sites to further constrain the nature of dark matter by future large spectroscopic surveys.
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Self-interacting dark matter (SIDM) models have the potential to solve the small-scale problems that arise in the cold dark matter paradigm. Simulations are a powerful tool for studying SIDM in the context of astrophysics, but it is numerically chall
enging to study differential cross-sections that favour small-angle scattering, as in light-mediator models. Here, we present a novel approach to model frequent scattering based on an effective drag force, which we have implemented into the N-body code gadget-3. In a range of test problems, we demonstrate that our implementation accurately models frequent scattering. Our implementation can be used to study differences between SIDM models that predict rare and frequent scattering. We simulate core formation in isolated dark matter haloes, as well as major mergers of galaxy clusters and find that SIDM models with rare and frequent interactions make different predictions. In particular, frequent interactions are able to produce larger offsets between the distribution of galaxies and dark matter in equal-mass mergers.
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