Interferometric mapping of magnetic fields: The ALMA view of the massive star forming clump W43-MM1

TL;DR

This study uses ALMA polarization observations to map magnetic fields in the massive star-forming region W43-MM1, revealing ordered magnetic structures, fragment properties, and evidence of gravitational influence on the magnetic field during collapse.

Contribution

First ALMA polarization mapping of W43-MM1 revealing magnetic field morphology and strength in a high-mass star-forming filament with implications for collapse dynamics.

Findings

Magnetic fields range from 0.2 to 9 mG across fragments.

All fragments are super-critical and likely collapsing.

Magnetic fields appear dragged by gravity during filament collapse.

Abstract

Here we present the first results from ALMA observations of 1 mm polarized dust emission towards the W43-MM1 high mass star forming clump. We have detected a highly fragmented filament with source masses ranging from 14Msun to 312Msun, where the largest fragment, source A, is believed to be one of the most massive in our Galaxy. We found a smooth, ordered, and detailed polarization pattern throughout the filament which we used to derived magnetic field morphologies and strengths for 12 out of the 15 fragments detected ranging from 0.2 to 9 mG. The dynamical equilibrium of each fragment was evaluated finding that all the fragments are in a super-critical state which is consistent with previously detected infalling motions towards W43-MM1. Moreover, there are indications suggesting that the field is being dragged by gravity as the whole filament is collapsing.