Regular distribution of star formation regions along the spiral arms and rings of disk galaxies

TL;DR

Recent high-resolution observations reveal that star formation regions in galaxy spiral arms and rings are regularly spaced at scales of 350-700 pc, challenging earlier models and supporting recent simulations.

Contribution

This study compiles observational evidence of regular star formation patterns across various galaxy types, highlighting a characteristic scale of 350-500 pc and comparing it with theoretical predictions.

Findings

Regular spacing of star formation regions at 350-500 pc.

Consistency of regularity across different galaxy morphologies.

Alignment with recent magneto-hydrodynamic simulation results.

Abstract

Last years studies have shown that the spatial regularity in the distribution of young stellar population along the spiral arms and rings of galaxies, previously considered to be rare, is a fairly common phenomenon. Spatial regularity has been found in the spiral arms and rings of galaxies of various morphology, from lenticular to extremely late-type spiral. The characteristic regularity scale is equal to 350-500 pc or a multiple thereof in all studied galaxies. Theoretical models predict a scale of instability of the stellar-gas disk on the order of a few kpc, which is several times larger than observed, although the most recent magneto-hydrodynamic simulations predict the formation of regular chains of star formation regions in spiral arms on a scale of 500-700 pc for the Milky Way-like galaxies. Modern high-quality surveys, such as PHANGS-MUSE, provide the necessary observational data (surface densities and velocity dispersions of gas and stellar population) to directly calculate the regularity scales in galaxies with high spatial resolution and wide field of view, which is a promising direction for research in this field.