Speaker
Description
Recent studies illustrate the correlation between the angular momenta of cosmic structures and their Lagrangian properties. However, only baryons are observable and it is unclear whether they reliably trace the cosmic angular momenta. We study the Lagrangian mass distribution, spin alignment, and conservation of dark matter (DM), gas, and stellar components of galaxy–halo systems using IllustrisTNG. We show that their protoshapes are similar in terms of the statistics of moment of inertia tensors. Under the common gravitational potential they are expected to be exerted the same tidal torque and generate strong spin direction and magnitude correlations. These correlations are not destroyed by the nonlinear evolution and complicated baryonic effects, except for the spin magnitude of stars, which is correlated with ex situ stellar mass fraction f_acc. We further show that the late-time angular momenta traced by total gas, stars, or the central galaxies, can be reliably reconstructed by the initial perturbations. These results suggest that baryonic angular momenta can potentially be used in reconstructing the parameters and models related to the initial perturbations.
