SMA Seminar 01/29/2021

The extended, fragile, collisional neutral hydrogen gas disks of galaxies are excellent diagnostic tracers of gravitational and hydrodynamic processes in the cosmic environment in which they are residing, and function as raw fuel for star formation. The morphology-density relation provides direct evidence that the cosmic environment of galaxies influences their morphologies and star formation activities. Within the virial radius of a galaxy cluster, both gravitational perturbations and hydrodynamic processes are at play. However, which of these processes dominate the transformation of infalling galaxies from star-forming and gas-rich, to quiescent and gas-poor is still unclear. I am investigating the influences of the global and local cosmic environments on the evolution of galaxies by studying the neutral hydrogen (HI) morphologies of galaxies in different locations of cluster substructures, and by in-depth, multi-wavelength case studies of so-called "jellyfish" galaxies. Taking advantage of MeerKAT data, I am currently studying in detail the spatially resolved HI morphologies and kinematics of the 219 HI detected galaxies in the entire volume of the Abell 2626 galaxy cluster, covering a wide range of cosmic environments. By identifying cluster substructures and characterising their environments, I investigate the relative importance and effects of the various physical mechanisms that are responsible for reshaping the galaxies. A preliminary analysis shows an increase of HI deficient galaxies towards the cluster core, indicating an increase in ram-pressure efficiency in the high-density cluster core. On a smaller scale, I am also studying the detailed cases of HI gas stripping in "jellyfish galaxies", the extreme examples of ram-pressure stripping with in situ star formation in the tails I have analysed the multi-phase (neutral, molecular, ionized gas) interstellar medium of the "jellyfish" galaxies JW100 and JO204 using multi-wavelength MeerKAT or JVLA, MUSE and ALMA observations. Both of these galaxies host an AGN in their centres and have active star formation in their stripped gas tails with an excess amount of molecular gas.