Early Results from the Coma Legacy IFU Survey (CLIFS): Ram Pressure Induced Shocks and Ionization in Jellyfish Tails

TL;DR

This study presents early findings on jellyfish galaxies in the Coma cluster, showing that ram pressure stripping induces shocks and ionization in their tails, with evidence of shock-excited diffuse ionized gas rather than star formation.

Contribution

First detailed emission line analysis of jellyfish galaxy tails in Coma, revealing shock-driven ionization caused by ram pressure stripping.

Findings

Evidence of shock-excited diffuse ionized gas in tails

Tail emission dominated by shocks, not star formation

Enhanced emission line ratios indicating RPS-driven shocks

Abstract

Jellyfish galaxies, which exhibit tails of gas opposite to their direction of motion, are a galaxy population showcasing the most extreme effects of ram pressure stripping (RPS). We present the emission line properties of a preliminary sample of five jellyfish galaxies in the Coma cluster, observed with the WEAVE Large-IFU as part of the Coma Legacy IFU Survey (CLIFS). When complete, CLIFS will form a sample of 29 jellyfish galaxies in Coma, selected based on the presence of one-sided tails in the radio continuum, enabling a comprehensive picture of the effects of ram pressure on galaxies in the Coma cluster. We extract emission line properties and confirm consistency between disk fluxes measured from WEAVE and MaNGA for galaxies with overlapping disk coverage between surveys. Comparing resolved radio and H$\alpha$-based star formation rates, we find that, in contrast to the disk, the dominant source of tail emission is not star formation. We find evidence for diffuse ionized gas excited by RPS-driven shocks in the tails, as indicated by: (1) LINER-like tail emission with the [OI]/H$\alpha$ BPT diagnostic; (2) enhanced [OII]/H$\alpha$ ratios in the tails relative to the disks; and (3) similarly elevated emission line velocities and velocity dispersions in the tails with respect to the disks. These results demonstrate that ram-pressure-driven shocks dominate the ionized emission in jellyfish galaxy tails.