The European Southern Observatory's Very Large Telescope was able to catch a glimpse of the galaxies for the first time as they were being illuminated by a quasar. Since the galaxies are bad at forming stars on their own, they're difficult to see without a light source like a quasar, which shines UV light and can cause a fluorescent glow in the starless galaxies. Their existence has been hinted at before, but this marks the first direct look.