arXiv subjects

Fang-Na Shao

Publications and source records attributed to Fang-Na Shao.

2 recordsLinked to original sources

arXiv2026

A high-significance detection of primordial tidal torque imprints

Tidal-torque theory predicts that galaxy angular momenta are imprinted by the primordial tidal field acting on proto-structures and that they can retain information about the early Universe through cosmic evolution. Here we test this prediction by comparing observed galaxy angular momentum vectors with those predicted from the primordial density field reconstructed by ELUCID for the nearby Universe. Among the galaxy populations considered, the gas component of central massive elliptical galaxies provides the clearest signal, exhibiting a strong direction correlation at a significance of about $7σ$. These results provide a robust observational evidence for tidal-torque theory and open a window for cosmological measurements of neutrino mass and other cosmological parameters.

astro-ph.CO↗

arXiv2026

Probing Primordial Chirality in the Matter Distribution

Whether parity symmetry was violated in the early universe remains one of the fundamental open questions in cosmology. If so, it may leave an intrinsic handedness in the large-scale matter distribution. Here we formulate a helicity-based estimator to measure this handedness. Using cosmological simulations with parity-violating initial conditions, we show that it survives nonlinear structure formation. Applying the estimator to density fields reconstructed from the SDSS DR7 galaxy catalog, we find mild deviations but statistically insignificant evidence for parity violation in the local universe. Our results establish the intrinsic handedness of the matter distribution as an observable relic of primordial parity violation, enabling a direct probe with current and future large-scale structure surveys.

astro-ph.CO↗