  Satellites of giant planets thought to form in gaseous circumplanetary disks
(CPDs) during the late planet-formation phase, but it was unknown so far
whether smaller mass planets, such as the ice giants could form such disks,
thus moons there. We combined radiative hydrodynamical simulations with
satellite population synthesis to investigate the question in the case of
Uranus and Neptune. For both ice giants we found that a gaseous CPD is created
at the end of their formation. The population synthesis confirmed that
Uranian-like, icy, prograde satellite-system could form in these CPDs within a
couple of $10^5$ years. This means that Neptune could have a Uranian-like
moon-system originally that was wiped away by the capture of Triton.
Furthermore, the current moons of Uranus can be reproduced by our model without
the need for planet-planet impact to create a debris disk for the moons to
grow. These results highlight that even ice giants -- that among the most
common mass-category of exoplanets -- can also form satellites, opening a way
to a potentially much larger population of exomoons than previously thought.
