Environmental processing of galaxies in H i-rich groups

Abstract

We present and explore the resolved atomic hydrogen (H i) content of 13 H i-rich and late-type dominated groups denoted ‘Choirs’. We quantify the H i content of the Choir galaxies with respect to the median of the H i-mass fraction (f$_{\rm {{\small H\,{I}}}}$) of their grandparent Hipass sample. We find that the H i mass fraction of the Choir galaxies is dispersed around the Hipass median in the range -1.4≤Δf$_{\rm {{\small H\,{I}}}}\rm {[dex]}\le$0.7, from H i-excess to H i-deficient galaxy regime. The H i-excess/H i-deficient galaxies contain more/less than 2.5 times their expected H i content with respect to the Hipass median. We show and discuss that the environmental processing in Choirs occurs via tidal stripping and galaxy mergers. Our analysis suggests that tidal stripping contributes to the loss of the H i, while galaxy mergers contribute to the enhancement of the H i. Exploring the mid-infrared properties of Choir galaxies we find possible environmental processing in only nine Choir galaxies, which indicates that environmental processing is more perceptible in the H i content than the mid-infrared properties. Moreover, we find that environmental processing occurs in Choir groups regardless of their global environment, whether they are in isolation or in proximity to the denser structures, such as cosmic web filaments. We explore possible scenarios of the Choirs evolution, taking into account their H i content, velocity dispersion, crossing time and their global environment. We conclude that the most likely evolution for the majority of Choir groups is that they will become more compact as their members undergo multiple H i-rich mergers.

Virgo filaments

“…The HI envelopes of HI-deficient galaxies in filaments have likely been stripped, possibly via tidal interactions or ram pressure. For HI, our proposed scenario is in agreement with the findings of Džudžar et al (2021), who investigated environmental processing in late-type-dominated groups using high-resolution HI observations. These latter authors further discussed the possibility that groups with the highest levels of processing are transitioning towards Hickson compact or fossil groups, which are environments similar to those associated with the isolated ellipticals in our AMIGA comparison sample.…”

The Three Hundred project: connection between star formation quenching and dynamical evolution in and around simulated galaxy clusters

“…As an example, Fabello et al (2012) found evidence that RP strips atomic gas of galaxies in haloes more massive than 10 13 M , whereas this should not be expected in lower mass haloes (Taranu & et al 2014). In addition, Džudžar et al (2021) suggest that tidal interactions are the primary cause of the H i deficiency in group galaxies, while Oh et al (2018) show evidence that mergers prior to infall can induce morphological transformation in recently accreted cluster galaxies. By means of the Yosei Zoom-in Cluster Simulations (YZiCS), which consist in the hydrodynamical simulations of 16 galaxy clusters that span masses of 5×10 13 < M 200 /M < 10 15 , Jung et al (2018) study the excess of gas-poor galaxies in cluster environments.…”