Gamma Ray Bursts versus OB Associations: do they trigger star formation?

TL;DR

This paper compares the effects of Gamma Ray Bursts and OB associations on the interstellar medium, focusing on the resulting structures' shapes, expansion velocities, and potential to trigger star formation.

Contribution

It provides a detailed analysis of how different energy sources influence ISM structures and explores the formation of arc-like features in galactic environments.

Findings

Supershells from GRBs are nearly static or slowly expanding.

OB association shells expand more rapidly.

Arc structures can form from expansion above or below the galactic plane.

Abstract

We discuss differences in shapes, expansion velocities and fragmentation times of structures created by an energy deposition from a single Gamma Ray Burst (GRB) or an OB association to the ISM. After the initial inflation, supershells produced by GRBs are almost static or slowly expanding, contrary to more rapidly expanding supershells created by OB associations. We discuss the position of the energy source relative to the symmetry plane of the galaxy: observed arc-like structures can be the most dense parts of structures formed by an expansion from a source above or below the galactic plane. Arcs may also form, if the expansion takes place inside a giant HI cloud. We try to reproduce the size, the age and the average distance between OB associations in the Sextant region at the edge of LMC 4.