  The characteristics of the particle emitting source are deduced from low
transverse momentum identified hadron spectra (transverse mass less than 1 GeV)
and HBT radii using a hydrodynamic interpretation. From the most peripheral to
the most central data, the single particle spectra are fit simultaneously for
all pions, kaons, and (anti-)protons using the parameterization in [1] and
assuming a linear transverse flow profile. Within the systematic uncertainties,
the expansion parameters called the freeze-out temperature and flow velocity,
respectively decrease and increase with the number of participants, saturating
for both at mid-centrality. The expansion using analytic calculations of the kT
dependence of HBT radii in [2] is fit to the data but no chi-squared minimum is
found.
