The effects of disk self-gravity and radiative cooling on the formation
  of gaps and spirals by young planets
  We have carried out two-dimensional hydrodynamical simulations to study the
effects of disk self-gravity and radiative cooling on the formation of gaps and
spirals. (1) With disk self-gravity included, we find stronger, more
tightly-wound spirals and deeper gaps in more massive disks. The deeper gaps
are due to the larger Angular Momentum Flux (AMF) of the waves excited in more
massive disks, as expected from the linear theory. The position of the
secondary gap does not change, provided that the disk is not extremely massive
($Q \gtrsim 2$). (2) With radiative cooling included, the excited spirals
become monotonically more open (less tightly-wound) as the disk's cooling
timescale increases. On the other hand, the amplitude and strength of the
spirals decrease when the cooling time increases from a small value to $\sim
1/\Omega$, but then the amplitude starts to increase again when the cooling
time continues to increase. This indicates that radiative dissipation becomes
important for waves with $T_{cool}\sim$ 1. Consequently, the induced primary
gap is narrower and the secondary gap becomes significantly shallower when the
cooling time becomes $\sim 1/\Omega$. When the secondary gap is present, the
position of it moves to the inner disk from the fast cooling cases to the slow
cooling cases. The dependence of gap properties on the cooling timescale (e.g.
in AS 209) provides a new way to constrain the disk optical depth and thus disk
surface density.
