  The formation of hot stars out of the cold interstellar medium lies at the
heart of astrophysical research. Understanding the importance of magnetic
fields during star formation remains a major challenge. With the advent of the
Atacama Large Millimeter Array, the potential to study magnetic fields by
polarization observations has tremendously progressed. However, the major
question remains how much magnetic fields shape the star formation process or
whether gravity is largely dominating. Here, we show that for the high-mass
star-forming region G327.3 the magnetic field morphology appears to be
dominantly shaped by the gravitational contraction of the central massive gas
core where the star formation proceeds. We find that in the outer parts of the
region, the magnetic field is directed toward the gravitational center of the
region. Filamentary structures feeding the central core exhibit U-shaped
magnetic field morphologies directed toward the gravitational center as well,
again showing the gravitational drag toward the center. The inner part then
shows rotational signatures, potentially associated with an embedded disk, and
there the magnetic field morphology appears to be rotationally dominated.
Hence, our results demonstrate that for this region gravity and rotation are
dominating the dynamics and shaping the magnetic field morphology.
