AAS 201st Meeting, January, 2003
Session 101. Cosmology and Gravitation
Oral, Wednesday, January 8, 2003, 10:00-11:30am, 612

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[101.06] Cold Dark Matter Halos and Disk Galaxy Rotation Curves

E. Hayashi, J. F. Navarro (University of Victoria)

Rotation curves of disk galaxies represent a crucial test of cold dark matter (CDM) dominated cosmological models. Observed rotation curves provide strong constraints on the total integrated mass of a galaxy as a function of radius and are therefore directly testable against the predictions of cosmological N-body simulations. We present the results of several high resolution simulations of galaxy-sized dark matter halos with resolution sufficent to resolve their circular velocity profiles down to the central 1-2 kpc.

We find that the density profiles of halos in our sample become progressively shallower at small radii, reaching a logarithmic slope shallower than -1.2 at the innermost points that are reliably measured. This tends to alleviate the discrepancy between the structure of CDM halos and the HI rotation curves of dwarf galaxies as noted by van den Bosch & Swaters (2001). The H\alpha rotation curve data of McGaugh, Rubin, & Deblok (2001), however, contain some examples where the shape of the rotation curve is difficult to reconcile with that of halos in our simulations.

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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.