  We present the Herschel Gould Belt survey maps of the L1641 molecular clouds
in Orion A. We extracted both the filaments and dense cores in the region. We
identified which of dense sources are proto- or pre-stellar, and studied their
association with the identified filaments. We find that although most (71%) of
the pre-stellar sources are located on filaments there is still a significant
fraction of sources not associated with such structures. We find that these two
populations (on and off the identified filaments) have distinctly different
mass distributions. The mass distribution of the sources on the filaments is
found to peak at 4 Solar masses and drives the shape of the CMF at higher
masses, which we fit with a power law of the form dN/dlogM \propto
M^{-1.4+/-0.4}. The mass distribution of the sources off the filaments, on the
other hand, peaks at 0.8 Solar masses and leads to a flattening of the CMF at
masses lower than ~4 Solar masses. We postulate that this difference between
the mass distributions is due to the higher proportion of gas that is available
in the filaments, rather than in the diffuse cloud.
