  We investigate whether a correlation exists between the concentration and
spin parameters of dark matter haloes forming in LCDM N-body simulations. In
particular, we focus on haloes with virial masses characteristic of the hosts
of Low Surface Brightness (LSB) and High Surface Brightness (HSB) galaxies. Our
analysis demonstrates that concentration and spin are anti-correlated. If we
assume that a galaxy disk forms in one of these haloes from baryons that
approximately conserved angular momentum during their dissipation into the
rotationally supported disk, then it is possible to estimate the disk's central
surface density. For an appropriate choice of mass-to-light ratio, we can place
constraints on the central surface brightness of the disk and hence identify
the analogues of the host haloes of LSB and HSB galaxies. We find that our LSB
galaxy analogues occupy haloes that have lower concentrations than might be
expected based on consideration of the mass-concentration relation for the LCDM
cosmology. The distribution of concentrations peaks at c~6, in good agreement
with observational data, although there are important differences between the
shapes of the simulated and observationally inferred distributions. This
suggests that LSB galaxies inhabit a biased subsample of the halo population,
and that this bias may be an important ingredient for resolving the current
debate regarding the structure of LSB galaxy dark matter haloes.

Astrophysics