The population of very low-mass satellites beyond the Local Group

The number and structural properties of the lowest-massgalaxies (less than ~10^6 Msun) that accompany galaxies like the Milky Way arekey to ruling out different dark matter models. However, this populationremains hidden beyond the Local Group due to its low brightness. In this study,we present the results of the LIGHTS survey in this area. With a currentsurface brightness limit of 31 mag/arcsec², LIGTHS is the deepest survey ofMilky Way–like galaxies beyond the local group to date (typical distance ~15Mpc). We will present the current detection limits and discuss what to expectfrom the next generation of ultra-deep surveys, such as LSST or Arrakhis.