Role of magnetic fields in ram pressure stripped galaxies

TL;DR

This paper investigates how magnetic fields influence the survival and star formation in the extended gas tails of ram-pressure stripped galaxies, combining observations and simulations to propose a magnetic draping scenario.

Contribution

It introduces a comprehensive model where magnetic draping shields stripped gas tails, enabling cooling and star formation, supported by multi-wavelength data and simulations of specific jellyfish galaxies.

Findings

Magnetic draping sheath protects tail gas from evaporation.

Stripped tail gas can cool and form stars due to magnetic effects.

Multi-phase gas studies support the proposed scenario.

Abstract

Ram-pressure stripping is a crucial evolutionary driver for cluster galaxies and jellyfish galaxies, characterized by very extended tails of stripped gas, are the most striking examples of it in action. Recently, those extended tails are found to show on-going star formation raising the question how the stripped, cold gas can survive long enough to form new stars outside the stellar disk. In this work, we summarize the most recent results achieved within the GASP collaboration to provide a holistic explanation for this phenomenon. We focus on two textbook examples of jellyfish galaxies, JO206 and JW100 for which, via multi-wavelength observations from radio to X-ray and numerical simulations, we have explored the different gas phases (neutral, molecular, diffuse-ionized, and hot). Based on additional multi-phase gas studies we now propose a scenario of stripped tail evolution including all phases that is driven by a magnetic draping sheath, where the intracluster turbulent magnetized plasma condenses onto the galaxy disk and tail and produces a magnetized interface that protects the stripped galaxy tail gas from evaporation. In such a scenario, the accreted environmental plasma can cool down and eventually join the tail gas, hence providing additional gas to form stars. The implications of our findings can shed light on the more general scenario of draping, condensation, and cooling of hot gas surrounding cold clouds that is fundamental in many astrophysical phenomena.