GASP XLV: Stellar Bars In Jellyfish Galaxies. Analysis of ionised gas and stellar populations

TL;DR

This study investigates how stellar bars and ram pressure influence star formation and stellar populations in galaxies, revealing that their combined effects can trigger central star formation and nuclear activity, especially in barred galaxies affected by ram pressure.

Contribution

It provides the first spatially resolved analysis of the combined impact of stellar bars and ram pressure on galaxy stellar populations using MUSE data.

Findings

Central SFR increases in ram pressure affected galaxies.

Barred galaxies at advanced ram pressure stages show star formation rejuvenation.

Nuclear activity correlates with suppressed star formation in some barred galaxies.

Abstract

Stellar bars have been found to substantially influence the stellar populations properties in galaxies, affecting their ability of forming stars. While this can be easily seen when studying galaxies in relatively isolated environments, such kind of analysis takes a higher degree of complexity when cluster galaxies are considered, due to the variety of interactions which can potentially occur in these denser environments. We use IFU MUSE data from the GASP survey to study the combined effect of the presence of a stellar bar and of ram pressure, on spatially resolved properties of stellar populations. We have analyzed spatially resolved indicators of both recent SFR and average stellar population ages to check for signatures of anomalous central SF activity, also taking into account for the possible presence of nuclear activity. We found an increase of central SFR in ram pressure affected galaxies when compared with unperturbed ones. The most extreme cases of increase SFR and central rejuvenation occur in barred galaxies that are at advanced stages of ram pressure stripping. For low-mass barred galaxies affected by ram pressure, the combined effect is a systematic enhancement of the star formation activity as opposed to the case of high-mass galaxies that present both enhancement and suppression. Barred galaxies that present a suppression of their star formation activity also present signatures of nuclear activity. Our results indicate that the combined effect of the presence of a bar and a strong perturbation by ram pressure is able to trigger the central SF activity and probably ignite nuclear activity.