Hydrogen tails, plumes, clouds and filaments

TL;DR

This paper reviews low surface brightness hydrogen structures like tails and filaments in interacting galaxy systems, highlighting their significance in understanding galaxy interactions and the potential of upcoming HI surveys.

Contribution

It provides a summary of observed HI features in galaxy interactions and discusses how future surveys combined with simulations can elucidate their origins and evolution.

Findings

HI features can span hundreds of kpc in galaxy systems.

Upcoming surveys like ASKAP will catalog these LSB structures extensively.

Numerical simulations are essential for understanding the origin of observed HI features.

Abstract

Here I present a brief review of interacting galaxy systems with extended low surface brightness (LSB) hydrogen tails and similar structures. Typically found in merging pairs, galaxy groups and clusters, HI features in galaxy surroundings can span many hundreds of kpc, tracing gravitational interactions between galaxies and ram pressure forces moving through the intra-group/cluster medium. Upcoming large HI surveys, e.g., with the wide-field (FOV = 30 square degrees) Phased Array Feeds on the Australian SKA Pathfinder (ASKAP), will provide a census of LSB structures in the Local Universe. By recording and comparing the properties (length, shape, HI mass, etc.) of these observed structures and their associated galaxies, we can - using numerical simulations - try to establish their origin and evolutionary path.