  To assess the potential role of magnetic fields in regulating the envelope
rotation and the fragmentation of Class 0 protostars, we carried out
observations of the dust polarized emission at 0.87 mm with the SMA, in the
envelopes of a large sample of 20 Class 0 protostars. We estimate the mean
magnetic field orientation over the central 1000 au envelope scales and
compared it to that of the protostellar outflow in order to study the relation
between their misalignment and the kinematics of the circumstellar gas. We
discover a strong relationship between the misalignment of the magnetic field
orientation with the outflow and the amount of angular momentum observed at
similar scales in the protostellar envelope, revealing a potential link between
the kinetic and the magnetic energy at envelope scales. The relation could be
driven by favored B misalignments in more dynamical envelopes or a dependence
of the envelope dynamics with the large-scale B initial configuration.
Comparing the trend with the presence of fragmentation, we observe that single
sources are mostly associated with conditions of low angular momentum in the
inner envelope and good alignment of the magnetic field with protostellar
outflows, at intermediate scales. Our results suggest that the properties of
the magnetic field in protostellar envelopes bear a tight relationship with the
rotating-infalling gas directly involved in the star and disk formation: we
find that it may not only influence the fragmentation of protostellar cores
into multiple stellar systems, but also set the conditions establishing the
pristine properties of planet-forming disks.
