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We present MeerKAT HI observations of six jellyfish candidate galaxies (JFCGs) in the galaxy cluster, A2626. Two of the six galaxies JW100 and JW103, that were identified as JFCGs from B-band images, are confirmed as jellyfish galaxies (JFGs). Both of the JFGs have low HI content, reside in the cluster core, and move at very high velocities ($\sim$ 3$\sigma_{cl}$). The other JFCGs, identified as non-jellyfish galaxies, are HI rich, with HI morphologies revealing warps, asymmetries, and possible tidal interactions. Both the A2626 JFGs and three other confirmed JFGs from the GASP sample show that these galaxies are HI stripped but not yet quenched. We detect HI, Halpha, and CO tails of similar extent ($\sim$ 50 kpc) in JW100. Comparing the multi-phase velocity channels, we do not detect any HI or CO emission in the northern section of the tail where Halpha emission is present, possibly due to prolonged interaction between the stripped gas and the ICM. We also observe an anti-correlation between HI and CO, which hints at an efficient conversion of HI to H2 in the southern part of the tail. We find that both RPS and HI-to-H2 conversion are significant depletion channels for atomic gas. HI-to-H2 conversion is more efficient in the disc than in the tail., Comment: 15 pages, 10 figures, accepted for publication in MNRAS

The extended, fragile, collisional atomic hydrogen (HI) gas discs in galaxies are excellent diagnostic tracers of gravitational and hydrodynamic processes in the cosmic environment they are residing in and also reservoirs for star formation. Within a galaxy cluster, both gravitational perturbations (tidal interactions, harassment, etc.) and hydrodynamic processes (thermal evaporation, ram pressure stripping (RPS), etc.) are at play. However, it is not clear yet which of these processes dominate the transformation of galaxies from star forming and gas rich, to quiescent and gas poor. I am investigating the influences of the global and local cosmic environment on the evolution of galaxies, both from the HI morphologies of galaxies in different locations of cluster substructures and the multi-wavelength case studies of the striking galaxies. From the new MeerKAT telescope observations of A2626 volume, I am studying the spatially resolved morphologies of the 219 HI detected galaxies, covering a range of cosmic environments. By identifying the cluster substructures and characterising their environments, I investigate the relative importance and effects of the various physical mechanisms that are responsible for reshaping galaxies. In addition, I am also studying the detailed cases of HI gas stripping in the “jellyfish galaxies”, the extreme examples of RPS with in-situ star formation in the tails. I have analysed the multi-phase (neutral, molecular, ionised gas) ISM of jellyfish galaxies JW100 and JO204 from multi-wavelength MeerKAT or JVLA, MUSE and ALMA observations.