Synchrotron radiation from molecular clouds

TL;DR

This paper explores the potential of high-resolution radio observations, like those from the SKA, to detect synchrotron radiation from molecular clouds, enabling direct measurement of magnetic fields crucial for star formation understanding.

Contribution

It proposes using radio synchrotron emission as a novel method to measure magnetic fields in molecular clouds, which has not been previously observed.

Findings

Synchrotron emission from molecular clouds is theoretically detectable.

Expected flux densities are around millijanskys at 1 GHz.

Detection with instruments like SKA is feasible.

Abstract

Observations of the properties of dense molecular clouds are critical in understanding the process of star-formation. One of the most important, but least understood, is the role of the magnetic fields. We discuss the possibility of using high-resolution, high-sensitivity radio observations to measure the in-situ synchrotron radiation from these molecular clouds. If the cosmic-ray particles penetrate clouds as expected, then we can measure the B-field strength directly using radio data. So far, this signature has never been detected from the collapsing clouds themselves and would be a unique probe of the magnetic field. Dense cores are typically ~0.05 pc in size, corresponding to ~arcsec at ~kpc distances, and flux density estimates are ~mJy at 1 GHz. They should be detectable, for example with the Square Kilometre Array.