On the origin of the absorption and emission line components in the spectra of PHL 293B

TL;DR

This paper explains the origin of emission and absorption lines in PHL 293B's spectrum by modeling the galaxy's structure, ionizing cluster, and hydrodynamic processes, identifying supernova remnants and cluster winds as key components.

Contribution

It provides a detailed physical model linking spectral features to specific astrophysical structures and processes in PHL 293B, supported by numerical and analytical calculations.

Findings

Narrow emission lines originate from an HII region in the galaxy.

Broad emission components are due to off-centered supernova remnants.

Absorption lines are caused by a stationary cluster wind.

Abstract

From the structure of PHL 293B and the physical properties of its ionizing cluster and based on results of hydrodynamic models, we point at the various events required to explain in detail the emission and absorption components seen in its optical spectrum. We ascribe the narrow and well centered emission lines, showing the low metallicity of the galaxy, to an HII region that spans through the main body of the galaxy. The broad emission line components are due to two off-centered supernova remnants evolving within the ionizing cluster volume and the absorption line profiles are due to a stationary cluster wind able to recombine at a close distance from the cluster surface, as originally suggested by Silich et al. (2004). Our numerical models and analytical estimates confirm the ionized and neutral column density values and the inferred X-ray emission derived from the observations.