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

T. C. Scott, E. Brinks, L. Cortese, A. Boselli, H. Bravo-Alfaro

Abstract

To investigate the effects the cluster environment has on late-type galaxies (LTGs), we studied H i perturbation signatures for all Abell 1367 LTGs with H i detections. We used new Very Large Array H i 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 H i spectrum as measured by the asymmetry parameter, Aflux⁠, can be a useful diagnostic for ongoing and/or recent H i stripping. 26 per cent of A1367 LTGs have an Aflux ratio, more asymmetrical than 3 times the 1σ spread in the Aflux ratio distribution of an undisturbed sample of isolated galaxies (2 per cent) and samples from other denser environments (10 per cent–20 per cent). Over half of the A1367 LTGs, which are members of groups or pairs, have an Aflux ratio larger than twice the 1σ spread found in the isolated sample. This suggests intergroup/pair interactions could be making a significant contribution to the LTGs displaying such Aflux ratios. The study also demonstrates that the definition of the H i offset from the optical centre of LTGs is resolution dependent, suggesting that unresolved AGES H i offsets that are significantly larger than the pointing uncertainties (>2σ), reflect interactions which have asymmetrically displaced, significant masses of lower density H i, while having minimal impact on the location of the highest density H i in resolved maps. The distribution of Aflux from a comparable sample of Virgo galaxies provides a clear indication that the frequency of H i profile perturbations is lower than in A1367.

Keywords
galaxies: clusters: individual: (Abell 1367); galaxies: clusters: intracluster medium; galaxies: evolution; galaxies: ISM; galaxies: interactions

Monthly Notices of the Royal Astronomical Society
Volume 475, Issue 4, Page 4648
2018 January

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Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia