The Herschel view of the dense core population in the Ophiuchus
  molecular cloud
  Herschel observations of nearby clouds in the Gould Belt support a paradigm
for low-mass star formation, starting with the generation of molecular
filaments, followed by filament fragmentation, and the concentration of mass
into self-gravitating prestellar cores. With the unique far-infrared and
submillimeter continuum imaging capabilities of the Herschel Space observatory,
the closeby (d = 139 pc) Ophiuchus cloud was mapped at five wavelengths from 70
${\mu}m$ to 500 ${\mu}m$ with the aim of providing a complete census of dense
cores in this region, including unbound starless cores, bound prestellar cores,
and protostellar cores. Taking advantage of the high dynamic range and
multi-wavelength nature of the Herschel data, we used the multi-scale
decomposition algorithms getsources and getfilaments to identify a complete
sample of dense cores and filaments in the cloud and study their properties.
The densest clouds of the Ophiuchus complex, L1688 and L1689, which thus far
are only indirectly described as filamentary regions owing to the spatial
distribution of their young stellar objects (YSOs), are confirmed to be
dominated by filamentary structures. The tight correlation observed between
prestellar cores and filamentary structures in L1688 and L1689 supports the
view that solar-type star formation occurs primarily in dense filaments. While
the sub clouds of the complex show disparities, L1689 being less efficient than
L1688 at forming stars when considering their total mass budgets, both sub
clouds share almost the same prestellar core formation efficiency in dense
molecular gas. We also find evidence in the Herschel data for a remarkable
concentric geometrical configuration in L1688 which is dominated by up to three
arc-like compression fronts and presumably created by shockwave events
emanating from the Sco OB2 association, including the neighboring massive (O9V)
star ${\sigma}$ Sco.
