Collisional debris as laboratories to study star formation

TL;DR

This study investigates star formation in collisional debris to determine whether local conditions or large-scale environment primarily influence the process, finding local properties are more significant.

Contribution

It provides multiwavelength observations of star-forming regions in collisional debris, highlighting the dominance of local factors over large-scale environment in star formation.

Findings

Star formation in debris regions follows typical luminosity and metallicity trends.

Dust emission levels are consistent with expectations based on luminosity and metallicity.

Local properties like density and dust content are more influential than large-scale environment.

Abstract

In this paper we address the question whether star formation is driven by local processes or the large scale environment. To do so, we investigate star formation in collisional debris where the gravitational potential well and velocity gradients are shallower and compare our results with previous work on star formation in non-interacting spiral and dwarf galaxies. We have performed multiwavelength spectroscopic and imaging observations (from the far-ultraviolet to the mid-infrared) of 6 interacting systems, identifying a total of 60 star-forming regions in their collision debris. Our analysis indicates that in these regions a) the emission of the dust is at the expected level for their luminosity and metallicity, b) the usual tracers of star formation rate display the typical trend and scatter found in classical star forming regions, and c) the extinction and metallicity are not the main parameters governing the scatter in the properties of intergalactic star forming regions; age effects and variations in the number of stellar populations, seem to play an important role. Our work suggests that local properties such as column density and dust content, rather than the large scale environment seem to drive star formation. This means that intergalactic star forming regions can be used as a reliable tool to study star formation.