Magnetic Fields in High-Mass Infrared Dark Clouds

TL;DR

This study presents the first measurements of magnetic fields in massive Infrared Dark Clouds, revealing strong magnetic influence that potentially regulates high-mass star formation by suppressing fragmentation.

Contribution

It provides the first observational evidence of strong magnetic fields in IRDCs prior to high-mass star formation, challenging existing theories that neglect magnetic effects.

Findings

IRDCs G11.11-0.12 and G0.253+0.016 are strongly magnetized.

Magnetic fields are as influential as turbulence and gravity in these clouds.

Magnetic fields can suppress fragmentation, facilitating high-mass star formation.

Abstract

High-mass Stars are cosmic engines known to dominate the energetics in the Milky Way and other galaxies. However, their formation is still not well understood. Massive, cold, dense clouds, often appearing as Infrared Dark Clouds (IRDCs), are the nurseries of massive stars. No measurements of magnetic fields in IRDCs in a state prior to the onset of high-mass star formation (HMSF) have previously been available, and prevailing HMSF theories do not consider strong magnetic fields. Here, we report observations of magnetic fields in two of the most massive IRDCs in the Milky Way. We show that IRDCs G11.11-0.12 and G0.253+0.016 are strongly magnetized and that the strong magnetic field is as important as turbulence and gravity for HMSF. The main dense filament in G11.11-0.12 is perpendicular to the magnetic field, while the lower density filament merging onto the main filament is parallel to the magnetic field. The implied magnetic field is strong enough to suppress fragmentation sufficiently to allow HMSF. Other mechanisms reducing fragmentation, such as the entrapment of heating from young stars via high mass surface densities, are not required to facilitate HMSF.