  We present H13CO+ (J=1-0) and HNC (J=1-0) maps of regions in Serpens South,
Serpens Main and NGC 1333 containing filaments. We also observe the Serpens
regions using H13CN (J=1-0). These dense gas tracer molecular line observations
carried out with CARMA have an angular resolution of ~7", a spectral resolution
of ~0.16 km/s and a sensitivity of 50-100 mJy/beam. Although the large scale
structure compares well with the Herschel dust continuum maps, we resolve finer
structure within the filaments identified by Herschel. The H13CO+ emission
distribution agrees with the existing CARMA N2H+ (J=1-0) maps; so they trace
the same morphology and kinematics of the filaments. The H13CO+ maps
additionally reveal that many regions have multiple structures partially
overlapping in the line-of-sight. In two regions, the velocity differences are
as high as 1.4 m/s. We identify 8 filamentary structures having typical widths
of 0.03-0.08 pc in these tracers. At least 50% of the filamentary structures
have distinct velocity gradients perpendicular to their major axis with average
values in the range 4-10 km/s/pc. These findings are in support of the
theoretical models of filament formation by 2-D inflow in the shock layer
created by colliding turbulent cells. We also find evidence of velocity
gradients along the length of two filamentary structures; the gradients suggest
that these filaments are inflowing towards the cloud core.
