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The morphology-density relation manifests the environmental dependence of the formation and evolution of galaxies as they continuously migrate through the cosmic web to ever denser environments. As gas-rich galaxies traverse the outskirts and inner regions of galaxy clusters they experience sudden and radical changes in their gas content and star formation activity. The goal of this work is to gain an H$,$I perspective on gas depletion mechanisms acting on galaxies and galaxy groups that are being accreted by a moderately massive galaxy cluster. We aim to study the relative importance and efficiency of processes such as ram-pressure stripping and tidal interactions as well as their dependency on the local and global environment of galaxies in the cluster core and in its surroundings. We have conducted a blind radio continuum and H$,$I spectral line imaging survey with the MeerKAT radio telescope of a 2$^circ$ $times$ 2$^circ$ area centred on the galaxy cluster Abell 2626. We have used the CARAcal pipeline to reduce the data, SoFiA to detect sources within the H$,$I data cube, and GIPSY to construct spatially resolved information on the H$,$I morphologies and kinematics of the H$,$I detected galaxies. We have detected H$,$I in 219 galaxies with optical counterparts within the entire surveyed volume. We present the H$,$I properties of each of the detected galaxies as a data catalogue and as an atlas page for each galaxy, including H$,$I column-density maps, velocity fields, position-velocity diagrams and global H$,$I profiles. These data will also be used for case studies of identified ``jellyfish galaxies and galaxy population studies by means of morphological classification of the direct H$,$I detections as well as using the H$,$I stacking technique.
We present the results of a survey for intervening HI 21-cm absorbers at intermediate and low redshift (0<z<1.2). For our total sample of 24 systems, we obtained high quality data for 17 systems, the other seven being severely affected by radio frequ
New MMT/Hectospec spectroscopy centered on the galaxy cluster A2626 and covering a ${sim} 1.8,text{deg}^2$ area out to $z sim 0.46$ more than doubles the number of galaxy redshifts in this region. The spectra confirm four clusters previously identifi
We report the detection of HI 21-cm absorption in a member of the rare and recently discovered class of compact radio sources, Extremely Inverted Spectrum Extragalactic Radio Sources (EISERS). EISERS conceivably form a special sub-class of the invert
This review summarises what we have learnt in the last two decades based on HI 21-cm absorption observations about the cold interstellar medium (ISM) in the central regions of active galaxies and the interplay between this gas and the active nucleus
The HI line at 21 cm is a tracer of circumstellar matter around AGB stars, and especially of the matter located at large distances (0.1-1 pc) from the central stars. It can give unique information on the kinematics and on the physical conditions in t