Curvature Mapping Method: Mapping Lorentz Force in Orion A

TL;DR

The paper introduces the Curvature Mapping Method, a new technique to map and evaluate the magnetic force's role in star formation regions using polarization data, applied to Orion A.

Contribution

It presents a novel method for mapping magnetic forces in star-forming regions, providing quantitative analysis of magnetic support against gravity.

Findings

Magnetic force can support low-density gas against gravity.

Magnetic force is insufficient to prevent collapse in dense regions.

The method effectively utilizes polarization maps for magnetic force estimation.

Abstract

Magnetic force is a fundamental force in nature. Although widely believed to be important in counterbalancing against collapse in star formation, a clear evaluation of the role of the magnetic field in star formation remains hard to achieve. Past research attempts to evaluate the importance of magnetic forces using diagnostics such as the mass-to-flux ratio, which measures its strength but not how it functions. Since star formation is a complex process and the observed regions have complex structures, mapping the importance of the magnetic field is necessary. We propose a new technique, the Curvature Mapping Method, to evaluate the role of the magnetic force by providing maps of the magnetic force estimated using polarization observations. The Curvature Mapping Method provides maps with the contribution of the magnetic force clearly outlined. We apply the method to the star formation region of Orion A and provide a first quantitative result where the magnetic force arising from the pinched magnetic field does provide support against gravity. By comparing it against the gravitational force, we find that the magnetic force is enough to affect the low-density gas but is insufficient to support the dense region from collapse. The method effectively uses information contained in polarization maps and can be applied to data from surveys to understand the role of the B-field.