Probing the structure of a massive filament: ArTeMiS 350 and 450 micron
  mapping of the integral-shaped filament in Orion A
  (abridged) Within the Orion A molecular cloud, the integral-shaped filament
(ISF) is a prominent, degree-long structure of dense gas and dust, with clear
signs of recent and on-going high-mass star formation. We used the ArTeMiS
bolometer camera at APEX to map a 0.6x0.2 deg^2 region covering OMC-1, OMC-2,
OMC-3 at 350 and 450 micron. We combined these data with Herschel-SPIRE maps to
recover extended emission. The combined Herschel-ArTeMiS maps provide details
on the distribution of dense, cold material, with a high spatial dynamic range,
from our 8'' resolution (0.016 pc) up to the size of the map ~10-15 deg. By
combining Herschel and ArTeMiS data at 160, 250, 350 and 450 micron, we
constructed high-resolution temperature and H2 column density maps. We
extracted radial profiles from the column density map in several,
representative portions of the ISF, that we fitted with Gaussian and Plummer
models to derive their intrinsic widths. We also compared the distribution of
material traced by ArTeMiS with that seen in the higher density tracer
N2H+(1-0) recently observed with the ALMA interferometer. All the radial
profiles that we extracted show clear deviation from a Gaussian, with evidence
for an inner plateau, previously not seen using Herschel-only data. We measure
intrinsic half-power widths in the range 0.06 to 0.11 pc. This is significantly
larger than the Gaussian widths measured for fibers seen in N2H+, which
probably traces only the dense innermost regions of the large-scale filament.
These half-power widths are within a factor of two of the value of 0.1 pc found
for a large sample of nearby filaments in various low-mass star-forming
regions, which tends to indicate that the physical conditions governing the
fragmentation of prestellar cores within transcritical or supercritical
filaments are the same over a large range of masses per unit length.
