Pedro Colín (UNAM)
"Is SIDM still a good substitute for collisionless CDM?"


In this talk, I am going to discuss the structure of halos as well as their subhalo population in a self-interacting dark matter (SIDM) cosmology. The cross-section per unit of particle mass, sigma, is taken constant or inversely proportional to the relative velocity, v12. The evolution of the density and the velocity dispersion halo profiles depends on the number of collisions per particle, nc, which in turn depends on the average of the product of sigma and v12. For a sigma inversely proportional to v12, this number nc is essentially independent on halo mass. When our numerical results on central densities or core sizes are compared with observations the constant sigma case is ruled out at the 1sigma level. On the other hand, when our results for the velocity dependent sigma case is compared with observations they agree within the observational errors. We notice that this is the first time in which this case is studied in SIDM N-body simulations.

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