  We have conducted aperture polarimetry of ~500 stars of the Orion Nebula
Cluster (ONC) in M42 based on our wide-field (~8'\times 8') $JHKs$ band
polarimetry.
  Most of the near-infrared (NIR) polarizations are dichroic, with position
angles of polarization agreeing, both globally and locally, with previous
far-infrared (FIR) and submillimeter observations, having taken into account
the 90$^\circ $ difference in angles between dichroic absorption and emission.
This is consistent with the idea that both NIR dichroic polarizations and
FIR/submillimeter thermal polarizations trace the magnetic fields in the OMC-1
region. The magnetic fields inferred from these observations show a pinch at
scales less than 0.5 pc with a centroid near IRc2. The hourglass-shaped
magnetic field pattern is explained by the models in which the magnetic field
lines are dragged along with the contracting gas and then wound up by rotation
in a disk. The highly polarized region to the northwest of IRc2 and the
low-polarized region near the bright bar are also common among NIR and
FIR/submillimeter data, although a few regions of discrepancy exist.
  We have also discerned ~50 possible highly polarized sources whose
polarizations are more likely to be intrinsic rather than dichroic. Their
polarization efficiencies ($P(H)/A(H)$) are too large to be explained by the
interstellar polarization. These include 10 young brown dwarfs that suggest a
higher polarization efficiency, which may present geometrical evidence for
(unresolved) circumstellar structures around young brown dwarfs.
