MUSE sneaks a peek at extreme ram-pressure stripping events - V. Towards a complete view of the galaxy cluster A1367

We present an analysis of the kinematics and ionization conditions in a sample composed of seven star-forming galaxies undergoing ram-pressure stripping in the A 1367 cluster, and the galaxy ESO137-001 in the Norma cluster. MUSE observations of two new galaxies in this sample, CGCG097-073 and CGCG097-079, are also presented. This sample is characterized by homogeneous integral field spectroscopy with MUSE and by a consistent selection based on the presence of ionized gas tails. The ratio [O I]/H alpha is consistently elevated in the tails of these objects compared to what observed in unperturbed galaxy discs, an ubiquitous feature which we attribute to shocks or turbulent phenomena in the stripped gas. Compact star-forming regions are observed in only approximate to 50 per cent of the tails, implying that specific (currently unknown) conditions are needed to trigger star formation inside the stripped gas. Focusing on the interface regions between the interstellar and intracluster medium, we observe different line ratios that we associate to different stages of the stripping process, with galaxies at an early stage of perturbation showing more prominent signatures of elevated star formation. Our analysis, thus, demonstrates the power of a well selected and homogeneous sample to infer general properties arising from ram-pressure stripping inside local clusters.

Automated summary

We analyze the kinematics and ionization conditions of star-forming galaxies undergoing ram-pressure stripping in the A 1367 cluster and ESO137-001 galaxy in the Norma cluster. MUSE observations of two new galaxies in the sample, CGCG097-073 and CGCG097-079, are also presented. Our findings reveal that the [O I]/H alpha ratio is consistently higher in the stripped gas tails, which we attribute to shocks or turbulent phenomena. Compact star-forming regions are observed in only approximately 50% of the tails, suggesting specific conditions are required to trigger star formation. The interface regions between interstellar and intracluster mediums exhibit different line ratios, indicating different stages of the stripping process.