SKA studies of in-situ synchrotron radiation from molecular clouds

TL;DR

This paper explores using the SKA radio telescope to detect in-situ synchrotron radiation from molecular clouds, enabling direct measurement of magnetic fields critical for understanding star formation.

Contribution

It proposes a novel method to detect synchrotron emission from molecular clouds with SKA, allowing direct magnetic field measurements previously unattainable.

Findings

SKA can detect synchrotron signals from dense cores (~0.05 pc) at kpc distances.

Potential to measure magnetic field strength directly from radio data.

Polarised synchrotron detection could reveal magnetic field structure.

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 with the SKA to measure for the first time the in-situ synchrotron radiation from these molecular clouds. If the cosmic-ray (CR) 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. The SKA should be able to readily detect directly, for the first time, along lines-of-sight that are not contaminated by thermal emission or complex foreground/background synchrotron emission. Polarised synchrotron may also be detectable providing additional information about the regular/turbulent fields.