Magnetic Seismology of Interstellar Gas Clouds: Unveiling a Hidden Dimension

TL;DR

This paper uses magnetic seismology to detect vibrational modes in the interstellar cloud Musca, revealing its true sheet-like 3D structure and advancing understanding of molecular cloud morphology.

Contribution

It introduces a novel application of magnetic seismology to determine the 3D structure of interstellar clouds, confirming Musca's sheet-like shape through observations and simulations.

Findings

Musca exhibits global vibrations consistent with a sheet morphology.

Normal vibrational modes enable 3D structural determination.

Simulations confirm the observed modes and morphology.

Abstract

Stars and planets are formed inside dense interstellar molecular clouds, by processes imprinted on the 3-dimensional (3D) morphology of the clouds. Determining the 3D structure of interstellar clouds remains challenging, due to projection effects and difficulties measuring their extent along the line of sight. We report the detection of normal vibrational modes in the isolated interstellar cloud Musca, allowing determination of the 3D physical dimensions of the cloud. Musca is found to be vibrating globally, with the characteristic modes of a sheet viewed edge-on, not a filament as previously supposed. We reconstruct the physical properties of Musca through 3D magnetohydrodynamic simulations, reproducing the observed normal modes and confirming a sheet-like morphology.