The Mysterious Radcliffe Wave

TL;DR

The Radcliffe Wave is a recently discovered, large-scale vertical oscillation of molecular clouds and stars in the Milky Way, with unclear origins, confirmed across multiple stellar and interstellar components, and possibly caused by external gravitational influences.

Contribution

This paper reviews the discovery, characteristics, and observational evidence of the Radcliffe Wave, highlighting its widespread detection and the current lack of understanding of its origin.

Findings

Radcliffe Wave is a narrow chain of molecular clouds with vertical oscillations.

Oscillations are confirmed in various stellar populations and interstellar dust.

The wave may be caused by external gravitational impacts, but its nature remains unclear.

Abstract

The review is devoted to the Radcliffe Wave recently discovered by Alves et al. from the analysis of molecular clouds. These authors singled out a narrow chain of molecular clouds, elongated almost in one line, located at an inclination of about 30$^o$ to the galactic axis y. The Radcliffe Wave itself describes damped vertical oscillations of molecular clouds with a maximum oscillation amplitude of about 160 pc and a characteristic wavelength of about 2.5 kpc. To date, the presence of the Radcliffe Wave has been confirmed in the vertical distribution of a) interstellar dust, b) sources of maser radiation and radio stars, which are very young stars and protostars closely associated with molecular clouds, c) low-mass stars of the T Tau type, d) more massive OB stars and e) young open clusters of stars. The Radcliffe Wave is also traced in the vertical velocities of young stars. Most of the considered results of the analysis of the vertical velocities of various young stars show that the oscillations of the vertical positions and vertical velocities of stars in the Radcliffe Wave occur synchronously. The nature of the Radcliffe Wave is completely unclear. The majority of researchers associate its occurrence with the assumption of an external gravitational impact on the galactic disk of a striker such as a dwarf satellite galaxy of the Milky Way.