Joint Astrophysical Colloquium
The MeerKAT Fornax Survey: paths to galaxy quenching in small clusters
Paolo Serra (INAF-OAC)
Thursday 28/11/2024 @ 11:30, Sala Antonio Sollima (IV piano Battiferro)
I will show science results from the MeerKAT Fornax Survey. Our goal is to perform a detailed study of the nearby Fornax galaxy cluster in order to understand how galaxies lose their cold gas and stop forming stars in low-mass clusters (Mvir < 1e+14 Msun). We are doing so through very deep (down to ~1e+18/cm^2) and high resolution (up to ~ 1kpc and 1 km/s) MeerKAT observations of HI gas in a 1x2 Mpc^2 region centred on Fornax. Our survey started in October 2020 and is now approaching completion. In this talk I will focus on the central region of the Fornax cluster, where our data reveal for the first time the ubiquitous presence of tails and clouds of HI. Some of the HI is clearly being removed from Fornax galaxies. Our analysis shows that, in relatively massive galaxies, the removal proceeds in two steps: first, a tidal interaction, which stirs up the gas and weakens its gravitational binding to the host galaxy; second, a hydrodynamical interaction with the intra-cluster medium, which pulls the tidally-perturbed gas further away from the host. In smaller galaxies, hydrodynamical forces alone are able to remove the HI on a short timescale, as I will discuss based on our study of the HI content of Fornax' dwarf galaxies and based on the Fornax' HI mass function.