L1495 Revisited: A PPMAP View of a Star-Forming Filament
  We have analysed the Herschel and SCUBA-2 dust continuum observations of the
main filament in the Taurus L1495 star forming region, using the Bayesian
fitting procedure PPMAP. (i) If we construct an average profile along the whole
length of the filament, it has fwhm $\simeq 0.087\pm 0.003\,{\rm pc};\;$, but
the closeness to previous estimates is coincidental. (ii) If we analyse small
local sections of the filament, the column-density profile approximates well to
the form predicted for hydrostatic equilibrium of an isothermal cylinder. (iii)
The ability of PPMAP to distinguish dust emitting at different temperatures,
and thereby to discriminate between the warm outer layers of the filament and
the cold inner layers near the spine, leads to a significant reduction in the
surface-density, $\varSigma$, and hence in the line-density, $\mu$. If we adopt
the canonical value for the critical line-density at a gas-kinetic temperature
of $10\,{\rm K}$, $\mu_{_{\rm CRIT}}\simeq 16\,{\rm M_{_\odot}\,pc^{-1}}$, the
filament is on average trans-critical, with ${\bar\mu}\sim \mu_{_{\rm
CRIT}};\;$ local sections where $\mu >\mu_{_{\rm CRIT}}$ tend to lie close to
pre-stellar cores. (iv) The ability of PPMAP to distinguish different types of
dust, i.e. dust characterised by different values of the emissivity index,
$\beta$, reveals that the dust in the filament has a lower emissivity index,
$\beta\leq1.5$, than the dust outside the filament, $\beta\geq 1.7$, implying
that the physical conditions in the filament have effected a change in the
properties of the dust.
