MeerKAT Legacy Local Universe Survey

Brief description of project: The MeerKAT Legacy Local Universe Survey (LLUS) is a three year, 800 hour survey of the atomic neutral hydrogen (HI) and full polarization radio continuum from 133 nearby (D < 20 Mpc) galaxies, which we will combine with the archive to produce a complete legacy survey of all 188 late-type, nearby southern galaxies with log M* > 9. We will combine these with optical and near-IR mapping now underway by Rubin LSST, Euclid, and SphereX, and with the latest hydrodynamical simulations to form a next generation view of gas and stars that probes into the low mass regime where dark-matter dominates the potential and HI dominates the gas reservoir. We will use the data to measure the resolved rotation curves and model the mass distributions in galaxies, and then compare to numerical simulations to test models of dark matter and anchor the stellar mass-halo mass relation. Leveraging MeerKAT's large field of view, we will find all gas-rich dwarf galaxies with

log M(HI) > 6 and measure the HI content for every satellite found by Euclid or Rubin LSST thus providing critical constraints on the evolution of satellite galaxies. We will also constrain the fueling of star formation by measuring the gas inflow/outflow rate through galaxies and assessing the distribution of extended HI around galaxies. Within galaxies, we will compare conditions in the HI and

the HI morphology to star formation activity and stellar structure to constrain models of stellar feedback and star formation.

The survey description

Status update: As of June 2026, we have observed the first nine galaxies in the sample. Processing of these data are ongoing. We plan for our first data release in May 2027.