Magnetic field properties in star formation: A review of their analysis methods and interpretation

Linearly polarized emission from dust grains and molecular spectroscopy is an effective probe of the magnetic field topology in interstellar medium clouds. The longstanding Davis-Chandrasekhar-Fermi (DCF) method recently developed Histogram Relative Orientations (HRO) analysis polarization-intensity gradient (KTH) are widely used to assess dynamic role fields star formation based on plane-of-sky component orientations inferred observations. We review advances limitations these methods summarize their applications Numerical tests DCF method, including its various variants, indicate that largest uncertainty may come assumption energy equipartition, which should be further calibrated with simulations suggest ordered turbulent particular observations local properties considered region. An polarization using estimations suggests magnetically trans-to-super-critical averagely trans-to-super-Alfvénic clumps/cores form sub-critical High-mass star-forming regions more gravity-dominant than low-mass counterparts due higher column density. observational HRO studies clearly reveal preferential relative orientation between density structures changes parallel perpendicular increasing densities, which, conjunction simulations, ongoing trans-to-sub-Alfvénic There a possible transition back random alignment at densities. Results KTH broadly agree those studies.