Properties of Starless and Prestellar Cores in Taurus Revealed by
  Herschel SPIRE/PACS Imaging
  The density and temperature structures of dense cores in the L1495 cloud of
the Taurus star-forming region are investigated using Herschel SPIRE and PACS
images in the 70 $\mu$m, 160 $\mu$m, 250 $\mu$m, 350 $\mu$m and 500 $\mu$m
continuum bands. A sample consisting of 20 cores, selected using spectral and
spatial criteria, is analysed using a new maximum likelihood technique,
COREFIT, which takes full account of the instrumental point spread functions.
We obtain central dust temperatures, $T_0$, in the range 6-12 K and find that,
in the majority of cases, the radial density falloff at large radial distances
is consistent with the $r^{-2}$ variation expected for Bonnor-Ebert spheres.
Two of our cores exhibit a significantly steeper falloff, however, and since
both appear to be gravitationally unstable, such behaviour may have
implications for collapse models. We find a strong negative correlation between
$T_0$ and peak column density, as expected if the dust is heated predominantly
by the interstellar radiation field. At the temperatures we estimate for the
core centres, carbon-bearing molecules freeze out as ice mantles on dust
grains, and this behaviour is supported here by the lack of correspondence
between our estimated core locations and the previously-published positions of
H$^{13}$CO$^+$ peaks. On this basis, our observations suggest a
sublimation-zone radius typically $\sim 10^4$ AU. Comparison with
previously-published N$_2$H$^+$ data at 8400 AU resolution, however, shows no
evidence for N$_2$H$^+$ depletion at that resolution.
