1208.3537 (Xiaolei Zhang)

Rapid Secular Radial Mass Accretion in N-Body Simulated Galaxy Disks    [PDF]

Xiaolei Zhang

Recent studies have indicated that large mass radial inflow rates are possible in observed galaxies with strong density wave patterns. Yet, numerical simulations have generally failed to account for such high rates. Here it is shown that the reason for the discrepancy is the treatment of "softening", the artificial parameter inserted by numerical simulators into the formula for gravitational potential, to control the magnitude of relaxation in simulations with small numbers of particles compared to a real galaxy. Excess softening reduces the collective effects underlying the significant secular evolution inferred for physical galaxies. Less softening, coupled with an increase in number of particles, allow the N-body simulations to reveal significant morphological transformation of galaxies over a Hubble time.

View original: http://arxiv.org/abs/1208.3537