Gravito-turbulence in local disk simulations with an adaptive moving mesh

Abstract

Self-gravity plays an important role in the evolution of rotationally supported systems such as protoplanetary disks, accretion disks around black holes, or galactic disks, as it can both feed turbulence or lead to gravitational fragmentation. While such systems can be studied in the shearing box approximation with high local resolution, the large density contrasts that are possible in the case of fragmentation still limit the utility of Eulerian codes with constant spatial resolution. In this paper, we present a novel self-gravity solver for the shearing box based on the TreePM method of the moving-mesh code AREPO. The spatial gravitational resolution is adaptive which is important to make full use of the quasi-Lagrangian hydrodynamical resolution of the code. We apply our new implementation to two- and three-dimensional, self-gravitating disks combined with a simple $\beta$-cooling prescription. For weak cooling we find a steady, gravito-turbulent state, while for strong cooling the formation of fragments is inevitable. To reach convergence for the critical cooling efficiency above which fragmentation occurs, we require a smoothing of the gravitational force in the two dimensional case that mimics the stratification of the three-dimensional simulations. The critical cooling efficiency we find, $\beta \approx 3$, as well as box-averaged quantities characterizing the gravito-turbulent state, agree well with various previous results in the literature. Interestingly, we observe stochastic fragmentation for $\beta >3$, which slightly decreases the cooling efficiency required to observe fragmentation over the lifetime of a protoplanetary disk. The numerical method outlined here appears well suited to study the problem of galactic disks as well as magnetized, self-gravitating disks.

20 pages, 16 figures, accepted by MNRAS

References in corpus (19)

• Simulating cosmic structure formation with the GADGET-4 code
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk
• Characterising the Gravitational Instability in Cooling Accretion Discs
• Fragmentation of Massive Protostellar Disks
• Type I planetary migration in a self-gravitating disk
• Treating gravity in thin disk simulations
• Convergence of the critical cooling rate for protoplanetary disk fragmentation achieved; the key role of numerical dissipation of angular momentum
• The response of self-graviting protostellar discs to slow reduction in cooling timescale: the fragmentation boundary revisited
• The fragmentation criteria in local vertically stratified self-gravitating disk simulations
• Gravito-Turbulent Disks in 3D: Turbulent Velocities vs. Depth
• Formation of intermediate-mass planets via magnetically-controlled disk fragmentation
• Gravito-turbulence and the excitation of small-scale parametric instability in astrophysical discs
• Magnetorotational instability and dynamo action in gravitoturbulent astrophysical discs
• Characterizing gravito-turbulence in 3D: turbulent properties and stability against fragmentation
• Nonlinear outcome of gravitational instability in an irradiated protoplanetary disc
• A two-step gravitational cascade for the fragmentation of self-gravitating discs
• Simulating the magnetorotational instability on a moving mesh with the shearing box approximation
• Simulating cold shear flows on a moving mesh

Cited by in corpus (3)

• Vertical shear instability with dust evolution and consistent cooling times. On the importance of the initial dust distribution
• An efficient spectral Poisson solver for the nirvana-III code: the shearing-box case with vertical vacuum boundary conditions
• How two-dimensional are planet-disc interactions? II. Radiation hydrodynamics and suitable cooling prescriptions