Some screenshots of the DTFE method
The Delaunay tessellation in 2D. Upper left: the 2D point distribution. Upper right: the Delaunay tessellation of the point distribution. Lower panels: A zoom of Delaunay tessellation in a high density region.
A volume rendering of the DTFE density field in a 100x100x20 Mpc slice.
A stereo view of a volume rendering of the DTFE density field in a 100x100x20 Mpc slice.
A comparison of the DTFE, SPH and TSC density field in a very thin 80x80x0.2 Mpc slice (the height of the slice is one grid cell):
- Upper left: DTFE density.
- Upper right: SPH density using 40 neighbors.
- Lower right: TSC density.
- Lower left: Absolute value of the DTFE velocity divergence.
All results are shown in a logarithmic scale.
A comparison of the DTFE, SPH and TSC density field in a 10 Mpc slice:
- Upper left: DTFE density.
- Upper right: SPH density using 40 neighbors.
- Lower right: TSC density.
- Lower left: Absolute value of the DTFE velocity divergence.
All results are shown in a logarithmic scale.
A comparison of the DTFE and SPH density field and velocity in a very thin 80x80x0.2 Mpc slice (the height of the slice is one grid cell):
- Upper left: DTFE density.
- Upper right: SPH density using 40 neighbors.
- Lower right: SPH velocity field in the plane (using 40 neighbors).
- Lower left: DTFE velocity field in the plane.
The density is shown in a logarithmic scale while the size of the velocity arrows is proportional to the velocity magnitude. The velocity vectors are also colored according to the velocity magnitude.
A comparison of the DTFE and SPH density field and velocity in a very thin 80x80x0.2 Mpc slice (the height of the slice is one grid cell):
- Upper left: DTFE density.
- Upper right: SPH density using 40 neighbors.
- Lower right: SPH velocity field in the plane (using 40 neighbors).
- Lower left: DTFE velocity field in the plane.
The density is shown in a logarithmic scale. All the velocity arrows have a constant size to better show the flow directions. The velocity vectors are also colored according to the velocity magnitude.
A logarithmic scale view of the DTFE density and velocity divergence fields in a very thin 100x100x0.4 Mpc slice (the height of the slice is one grid cell):
- Left: DTFE density field.
- Center: Absolute value of the DTFE velocity divergence.
- Right: Absolute value of the velocity divergence computed by differentiation on the grid. This is done by first computing the DTFE velocity field, after which the velocity divergence was computed in Fourier Space.
All results are shown in a logarithmic scale. The DTFE velocity divergence captures much better the structure in the void regions (compare the central and right panels).
A logarithmic scale view of the DTFE density and velocity divergence fields in a very thin 100x100x0.4 Mpc slice (the height of the slice is one grid cell):
- Left: DTFE density field.
- Center: The DTFE velocity field at the grid point position.
- Right: The DTFE velocity field volume averaged over the entire grid cell.
The density is shown in a logarithmic scale while the size of the velocity arrows is proportional to the velocity magnitude. The velocity vectors are also colored according to the velocity magnitude. In the DTFE program one can select between quantities interpolated at grid points or quantities averaged over the entire grid cell.
The DTFE density and velocity fields in a very thin 100x100x0.4 Mpc slice (the height of the slice is one grid cell):
- Left: DTFE density field.
- Center: The DTFE velocity field at the grid point position.
- Right: The DTFE velocity field volume averaged over the entire grid cell.
The density is shown in a logarithmic scale. All the velocity arrows have a constant size to better show the flow directions. The velocity vectors are also colored according to the velocity magnitude. In the DTFE program one can select between quantities interpolated at grid points or quantities averaged over the entire grid cell.