Abell 1367: a high fraction of late-type galaxies displaying HI morphological and kinematic perturbations

TL;DR

This study investigates how the cluster environment affects late-type galaxies in Abell 1367 by analyzing HI perturbation signatures, revealing that asymmetries in HI spectra are indicative of ongoing or recent gas stripping and interactions.

Contribution

It introduces the asymmetry parameter Aflux as a diagnostic tool for HI stripping and highlights the influence of group interactions on HI morphology in cluster galaxies.

Findings

26% of LTGs show significant HI asymmetry

Over half of group/paired LTGs have high Aflux ratios

HI profile perturbations are less frequent in Virgo compared to Abell 1367

Abstract

To investigate the effects the cluster environment has on Late-Type Galaxies (LTGs) we studied HI perturbation signatures for all Abell 1367 LTGs with HI detections. We used new VLA HI observations combined with AGES single dish blind survey data. Our study indicates that the asymmetry between the high-and low-velocity wings of the characteristic double-horn integrated HI spectrum as measured by the asymmetry parameter, Aflux, can be a useful diagnostic for ongoing and/or recent HI stripping. 26% of A1367 LTGs have an Aflux ratio, more asymmetrical than 3 times the 1{\sigma} spread in the Aflux ratio distribution of an undisturbed sample of isolated galaxies (2%) and samples from other denser environments (10% to 20%). Over half of the A 1367 LTGs, which are members of groups or pairs, have an Aflux ratio larger than twice the 1 {\sigma} spread found in the isolated sample. This suggests inter-group/pair interactions could be making a significant contribution to the LTGs displaying such Aflux ratios. The study also demonstrates that the definition of the HI offset from the optical centre of LTGs is resolution dependent, suggesting that unresolved AGES HI offsets that are significantly larger than the pointing uncertainties (> 2 {\sigma}) reflect interactions which have asymmetrically displaced significant masses of lower density HI, while having minimal impact on the location of the highest density HI in resolved maps. The distribution of Aflux from a comparable sample of Virgo galaxies provides a clear indication that the frequency of HI profile perturbations is lower than in A 1367.