Amazing stuff!
"Could galaxies be organized in a preferentially left- or right-handed way? Possible hints of such “parity violation” have been found in the way galaxies group together. In a new study ... explore whether a similar signal might be visible in the way galaxies rotate. The researchers predict that galaxy-rotation maps could exhibit a parity-violating pattern that is strong enough to be detectable in upcoming galaxy surveys. ..."
From the abstract:
"We explore the potential of using late-time galaxy spins to test the parity symmetry of primordial vector fossils. Using 𝑁-body simulations, we analyze halo spins as a reliable proxy for galaxy spins to investigate the detectability of this effect.
We develop a novel approach to generate initial conditions (ICs) that have substantial parity asymmetry but do not alter the initial matter power spectrum. We construct the initial spin fields from the parity broken ICs and halo spin fields using late-time halos evolved from such ICs. Focusing on the helicity of these vector fields, we detect substantial asymmetry in the initial spin field. In addition, we find that over 50% of the initial spin field’s asymmetry remains in the late-time halo spin field on a range of scales.
Based on mock galaxy spin fields derived from the halo spin fields, we forecast that a maximum detection at 13𝜎 is possible with the final DESI BGS for the model considered in this analysis.
Our findings demonstrate that primordial vectorial parity violation survives nonlinear gravitational evolution, and thus, can be effectively probed with galaxy spins at late times."
Probing Vector Chirality in the Early Universe (no public access)
Cosmological simulations show that a left–right asymmetry in the early Universe could leave a mark in the distribution of galaxy rotations.
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