Major mergers of galaxy haloes: cuspy or cored inner density profile?

摘要: We present the results from a series of collisionless N-body simulations major mergers galaxy dark matter haloes with density profiles having either inner cusps or cores. Our range 2 × 10 5 to 7 particles, allowing us probe phase-space distribution particles in innermost regions (less than 0.005 virial radii) cold haloes, subject much recent debate. find that merger two cored yields halo and does not result cuspy profile seen many cosmological simulations. This is unchanged if we consider parent mass ratios 3 : 1 instead 1. Mergers second equal mass, on other hand, produce slightly reduced logarithmic slope. Cuspy once formed, therefore appear resilient mergers. velocity structure remnants be mildly anisotropic, Maxwellian near centre but outer portions final haloes. Violent relaxation effective only during early phase mergers, mixing likely dominant process at late times.