Martin Weinberg (UMass)
"Bars, Cusps, and Cores"

ABSTRACT

Simulations predict that the dark matter halos of galaxies should have central cusps, while those inferred from observed galaxies do not have cusps. I will describe the evolution of a cuspy halo by a disk bar and show that a disk bar, which should be ubiquitous in forming galaxies, can produce cores in cuspy CDM dark matter profiles within 5 bar orbital times. The dynamical mechanisms involved here are general to all interactions between the disk, satellites and a dark-matter halo. In particular, both the bar-cusp and satellite-cusp coupling depends on near-resonant dynamics. I will demonstrate that simulations with very high resolution are required to suppress the small-scale noise and resolve the dynamics properly.

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