Dependence of the stellar initial mass function on low-density environments

Determine whether the initial mass function of newly formed stars depends on gas density or galactic disk surface density, including in the peripheral regions of high-surface-brightness galaxies and throughout low-surface-brightness galaxy disks.

Background

The paper discusses whether the low star-formation rates and faintness of low-surface-brightness galaxies could be related to an anomalous stellar mass-to-light ratio caused by a top-light initial mass function. Existing spectral-modeling and ultraviolet studies cited by the authors do not establish a substantial difference in the initial mass function between low- and high-surface-brightness systems, but they also do not resolve whether the initial mass function varies systematically with the density of the gas or stellar disk.

The unresolved issue is relevant to both low-surface-brightness galaxies and the outer disks of normal galaxies, where star formation occurs at unusually low gas and stellar surface densities.