Ram Pressure Stripping in High-Density Environments

Abstract

Galaxies living in rich environments are suffering different perturbations able to drastically affect their evolution. Among these, ram pressure stripping, i.e. the pressure exerted by the hot and dense intracluster medium (ICM) on galaxies moving at high velocity within the cluster gravitational potential well, is a key process able to remove their interstellar medium (ISM) and quench their activity of star formation. This review is aimed at describing this physical mechanism in different environments, from rich clusters of galaxies to loose and compact groups. We summarise the effects of this perturbing process on the baryonic components of galaxies, from the different gas phases (cold atomic and molecular, ionised, hot) to magnetic fields and cosmic rays, and describe their induced effects on the different stellar populations, with a particular attention to its role in the quenching episode generally observed in high density environments. We also discuss on the possible fate of the stripped material once removed from the perturbed galaxies and mixed with the ICM, and we try to estimate its contribution to the pollution of the surrounding environment. Finally, combining the results of local and high redshift observations with the prediction of tuned models and simulations, we try to quantify the importance of this process on the evolution of galaxies of different mass, from dwarfs to giants, in various environments and at different epochs.

GASP XXXVII: The Most Extreme Jellyfish Galaxies Compared to Other Disk Galaxies in Clusters, an HI Study

“…In fact, Poggianti et al (2016a) found that the star-formation rate in the jellyfish galaxies is a factor two higher than in non-stripped galaxies in this sample. Several searches for a few galaxies undergoing rampressure stripping, with enhanced star-formation, and long ionized tails have been performed in Virgo (Boselli et al 2021), and in massive X-ray clusters at higher redshift (Ebeling et al 2014). These results are consistent with ours, with Ebeling et al (2014) finding that the jellyfish candidates at higher z outshine all the other disks in the clusters.…”

“…These observations have led to a natureversus-nurture debate where galaxies are thought to be different either because they were formed in higher density regions (nature) or because the environment affects their evolution. Although this debate is still not completely settled, there is a wealth of observations that show that galaxies do get affected by their environment (Cortese et al 2021;Boselli et al 2021). The main processes being invoked are gas-gas interactions and gravitational interactions.…”

The relevance of ram pressure stripping for the evolution of blue cluster galaxies as seen at optical wavelengths

“…In the last decades, much attention has been dedicated to ram pressure stripped galaxies and currently few hundreds galaxies have been confirmed to be undergoing a ram pressure event. A number of studies have characterized in detail individual galaxies, paving the way for further investigation, but until recently they mostly focused on small and sparse samples that prevent a detailed characterization of the incidence of such events (e.g., Fumagalli et al 2014;Merluzzi et al 2016;Fossati et al 2016;Boselli et al 2016;Consolandi et al 2017;Boselli et al 2018;Owers et al 2012;Boselli et al 2021, just to cite a few).…”

A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE).XII. Ionised gas emission in the inner regions of lenticular galaxies

“…Friedli & Martinet 1993, Laurikainen et al 2006, Masters et al 2010, Fraser-McKelvie et al 2018, Rizzo et al 2018, with an efficient gas ejection due to the feedback of an AGN (van den Bergh 2009), disc instabilities (Bournaud et al 2007, Bournaud 2016, the fading of the star formation activity of late-type galaxies due to the lack of fresh infalling gas once they become satellites of a larger halo (starvation, Larson et al 1980, Bekki et al 2002, the quenching of the star formation activity of spiral galaxies in rich clusters once their gas content has been removed during the interaction with the surrounding hostile environment (e.g. Quilis et al 2000, Burstein et al 2005, Boselli & Gavazzi 2006, Boselli et al 2021a, or more violent gravitational interactions (e.g. Byrd & Valtonen 1990, Dressler 2004, Bekki & Couch 2011 including galaxy harassment, minor and major merging events (e.g.…”