AGN fraction and metallicity in clusters and field: the role of ram pressure stripping

Active Galactic Nuclei (AGN) activity is one of the many processes involved in the so-called baryonic cycle, which broadly speaking is how the gas enters and exits the galaxy disks. Other mechanisms can affect the baryon cycle and some of them depend on the environment in which galaxies reside. In clusters, the largest structures in the universe, the ram-pressure (RP) exerted by the hot plasma filling the intra-cluster medium (ICM) is certainly one of the most efficient processes affecting gas inflows and outflows This Thesis aims to probe the interplay between the ram-pressure stripping (RPS) phenomenon and the AGN activity in nearby galaxies through the use of integral field spectroscopy (IFS) and the comparison of the observed data with ionization models. Throughout this dissertation, I present the results obtained by exploiting large samples of galaxies, divided according to the host galaxy's environment and the stage of AGN activity, by exploiting the Gas Stripping Phenomena (GASP) survey, which aims at studying the gas removal mechanisms in galaxies in different environments, in the local universe, and the integral field unit Mapping Nearby Galaxies at APO (MaNGA) survey, to build a control sample of undisturbed galaxies. First, I measure the incidence of AGN in clusters and in the field, in order to find for the first time statistical evidence of a link between RPS and the AGN activity. Then, I present a project focused on the measurement of the gas-phase metallicity in the nuclear regions of galaxies, in order to understand first of all the impact of the AGN on the global metallicity of the galaxy, also as a function of the host galaxy's stellar mass and the AGN's luminosity. With this project, I also aim to investigate the role of RPS on the AGN metallicity, since the two phenomena seem to work in synergy to quench star formation (thus, halting the metal production and the consequent ISM enrichment) in galaxies when these are acting together. Overall, I find that the AGN activity is somehow triggered by RPS and also that the AGN is releasing metals into the ISM. Particularly, I observe an enhancement of the metallicity at the centers of AGN hosts, but I conclude that the RPS is not playing a significant role in regulating the metal content in their nuclear regions. The final part is dedicated to a project aimed at deriving reliable gradients of metallicity by measuring in a spatially-resolved and homogeneous way the metallicity of the gas phase in regions ionized by stars, AGN, or a mixing of both. I find that the metal enrichment is actually tracing the impact of the AGN on the host galaxy, since the enhancement is limited to the nuclear regions, while H II regions in the galactic disk of SF and AGN galaxies are equally more metal-poor with respect to the centers. Overall, this Thesis demonstrates the power of multi-wavelength IFS studies to explore the impact of the environment on the properties of local galaxies. The use of large IFS programs, such as the GASP and MaNGA surveys, allows me to study in a statistically robust way the interplay between RPS and AGN activity by comparing the galaxies properties, disturbed or not by the RPS, both in a global and spatially-resolved way. The results obtained represent a unique test bench for the new generation of photoionisation models given both the capability of the H II models to reproduce even the strongest emission of the forbidden lines observed in H II regions and the ability to measure the gas metallicity with an homogeneous method in case of different ionization sources, thanks to the consistent assumptions made to generate the AGN and H II models.