Speaker
Description
Jellyfish galaxies have tentacles of material that stretch tens of kpc beyond their disks. These tentacles show signatures of ram-pressure stripping that happens when the hot, dense and powerful ICM pressure blows the gas out of the gravitational potential of the galaxies and creates tail-like structures out of the disk, stimulating star formation within them. The GASP (GAs Stripping Phenomena in galaxies) survey is carried out with the MUSE Integral Field spectrograph on the VLT to observe over 100 of these galaxies over a wide range of masses, morphological asymmetries and environments. Five of the most striking jellyfish galaxies are observed with the VLA-C array. JO204 is one such spectacular jellyfish galaxy in the relatively low-mass cluster A957 that shows a tail of ionized gas extending up to 30 kpc. From APEX data, we found a lot of molecular gas in the disk and in the ionized gas tail. I present the VLA HI data that provides missing information about the neutral gas phase. From the VLA observation of JO204, the HI content of this galaxy and the interplay between various gas phases is studied in detail. The HI tail is much more extended than the ionized gas tail and its unilateral extension is a distinct signature of ram-pressure stripping. We have also detected HI in absorption for the first time in this jellyfish galaxy against the 11 mJy central continuum source, which is an AGN. The red-shifted absorption profile of JO204 suggests that ram-pressure is pushing the HI gas towards the central black hole and thus triggering the AGN activity.
