Formation of satellites in circumplanetary discs generated by disc instability.

We investigated the formation and evolution of satellite systems in a cold, extended circumplanetary disc around a 10 $M_{\rm{Jupiter}}$ gas giant which was generated by gravitational instability. We use a population synthesis approach, in which we seed the disc with satellite embryos and let them migrate, accrete mass, collide, with subsequent generations being created until the disc is dissipated. In each run we choose randomly the dust-to-gas ratio, dispersion- and refilling time-scales, the number of embryos and their starting locations in a plausible range. The disc structure is the result of a 3D global disc SPH simulation \citep{Szulagyi16b}. We also investigate the effect of the planet's semi-major axis on the resulting satellite systems, taking 50 AU as the nominal case. In the nominal case we find that most satellites are close in mass to the Galilean ones, with a maximum at around 3 $M_{\rm{Earth}}$ and form typically on time-scales comparable to the dispersion time-scale. We also find that about 10 $M_{\rm{Earth}}$ worth of satellites migrate into the planet, polluting it with metals. The influence of a different planet semi-major axis is mainly felt through the change in disc size. We find that for the discs closer to the star, the satellites are lighter, formation time-scales are longer, and more moons are lost into the planet, as a smaller disc means easier migration for the massive satellites. The probability of detecting satellites like the ones in this work is very low ($\leq$ 3%) even with upcoming powerful telescopes like E-ELT.