Cosmological numerical simulations invariably produce cuspy dark
halos, but the precise value of the inner slope
of the
radial density profile
~
r
is debated.
Moore et al. (1999)
and Fukushige & Makino
(2001)
advocate = -1.5, and
Navarro, Frenk & White
(1996,
1997)
an inner slope of -1.0. Both White and
Navarro (this volume) report on work by
Hayashi et al. (2003) :
there is no real convergence towards a unique value of
the inner slope, the resolution prohibits
predictions to be made inside a radius
of ~ 1 kpc, but the profile remains cuspy, and there is
some cosmic scatter (see also
Fukushige, Kawai &
Makino 2003).
This situation differs from an until recently widespread perception that the NFW profile, with inner slope -1.0, should be considered "universal", and the yardstick against which the observations should be discussed. I will use the slope -1.0 here as a fiducial mark to see where the observations stand, and which is to be improved as the cosmological numerical simulations become more realistic (e.g. by having adequate resolution on the dwarf galaxy scale, and perhaps incorporating more relevant physics), and better understood theoretically (e.g. by demonstrating which physical process, or combination of processes, sets up the value of the inner slope in dark matter dominated galaxies).