Rotating filament in Orion B: Do cores inherit their angular momentum
  from their parent filament?
  Angular momentum is one of the most important physical quantities that govern
star formation. The initial angular momentum of a core may be responsible for
its fragmentation and can have an influence on the size of the protoplanetary
disk. To understand how cores obtain their initial angular momentum, it is
important to study the angular momentum of filaments where they form. While
theoretical studies on filament rotation have been explored, there exist very
few observational measurements of the specific angular momentum in star-forming
filaments. We present high-resolution N2D+ ALMA observations of the LBS 23
(HH24-HH26) region in Orion B, which provide one of the most reliable
measurements of the specific angular momentum in a star-forming filament. We
find the total specific angular momentum ($4 \times 10^{20} cm^2s^{-1}$), the
dependence of the specific angular momentum with radius (j(r) $\propto
r^{1.83}$), and the ratio of rotational energy to gravitational energy
($\beta_{rot} \sim 0.04$) comparable to those observed in rotating cores with
sizes similar to our filament width ($\sim$ 0.04 pc) in other star-forming
regions. Our filament angular momentum profile is consistent with rotation
acquired from ambient turbulence and with simulations that show cores and their
host filaments develop simultaneously due to the multi-scale growth of
nonlinear perturbation generated by turbulence.
