Are TNG peculiar velocities informed by large-scale gravitational effects beyond the box size, and if so, how? More specifically, do they account for the spatial frequency modes of the matter power spectrum with wavelengths longer than the box size?
For context, I am relating TNG300-3 subhalo peculiar velocity calculations to a theoretical curve based on the matter power spectrum. If I integrate the matter power spectrum over a large range of spatial frequencies, the TNG curves fall well below the theoretical curves, but if I integrate with k_min=2pi/box_size, the lowest frequency mode contained within a box-sized region, the theory and simulation results agree quite well. I want to verify if this could be explained by TNG's handling of large-scale peculiar velocity effects.
Dylan Nelson
23 Jun
The simulations have periodic boundaries, so they do not (cannot) include any effects beyond this scale.
For similar measurements and discussion you can look at Springel+18. You could compare your matter power spectrum measurement with one directly in that paper, to make sure it is consistent.
Are TNG peculiar velocities informed by large-scale gravitational effects beyond the box size, and if so, how? More specifically, do they account for the spatial frequency modes of the matter power spectrum with wavelengths longer than the box size?
For context, I am relating TNG300-3 subhalo peculiar velocity calculations to a theoretical curve based on the matter power spectrum. If I integrate the matter power spectrum over a large range of spatial frequencies, the TNG curves fall well below the theoretical curves, but if I integrate with k_min=2pi/box_size, the lowest frequency mode contained within a box-sized region, the theory and simulation results agree quite well. I want to verify if this could be explained by TNG's handling of large-scale peculiar velocity effects.
The simulations have periodic boundaries, so they do not (cannot) include any effects beyond this scale.
For similar measurements and discussion you can look at Springel+18. You could compare your matter power spectrum measurement with one directly in that paper, to make sure it is consistent.