Tracing the magnetic field morphology of the LDN 1172/1174 cloud complex
  The LDN 1172/1174 cloud complex in the Cepheus Flare region presents a
hub-filament structure with the reflection nebula, NGC 7023, illuminated by a
Herbig Be star, HD 200775, which consists of the hub with a $\sim$5 pc long
narrow filament attached to it. Formation of a sparse cluster of low- and
intermediate-mass stars is presently taking place in the hub. The aim of this
work is to map the magnetic field geometry of LDN 1172/1174 to understand the
role played by the field lines in the formation of the molecular cloud. We made
R-band polarization measurements of 249 stars projected on the entire LDN
1172/1174 cloud complex to map the geometry of the magnetic field of this
region. The magnetic field geometry constructed from our R-band polarization
measurements is found to be parallel to the elongated structure inferred from
the column density distribution of the cloud produced using the Herschel
images. Our R-band polarization measurements are found to be in good agreement
with those obtained from Planck. There is evidence of a possible distortion of
the magnetic fields toward the northwestern part of the cloud by HD 200775. The
magnetic field strength is estimated as $\sim$30 $\mu$G. The estimated star
formation rate (SFR)/mass of 2.0$\pm$1.3 \%Myr$^{-1}$ and 0.4$\pm$0.3
\%Myr$^{-1}$ for LDN 1172/1174 and the neighboring cloud complex, LDN
1147/1158, respectively, are found to be consistent with the mean SFR/mass
found for the clouds with magnetic field orientations parallel and
perpendicular to their elongated structures, respectively. These results
support earlier findings that the clouds with magnetic field lines parallel to
their long axes seem to have higher SFRs compared to those with the magnetic
field orientation perpendicular to the cloud elongation.
