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Title: Probing Parity Violation in the Early Universe using Galaxy Spins

Speaker: Dr. Junsup Shim (ASIAA)

Date&Time: 2024-11-08, 11:00 AM

Location: Science Hall B102

Talk to be delivered in English
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Abstract: Parity symmetry is a fundamental principle in physics, making its violation a key indicator of new physics beyond the standard models. Recently, there were 3-7 detections of parity asymmetry in the observed galaxy distribution, motivating further searches for potential signatures of primordial parity violation. In this talk, | will discuss the detectability of parity violation in primordial vector fossils using late-time galaxy spins. Using halo spins as proxies for galaxy spins, we examine the persistence of primordial parity asymmetry at low redshifts with N-body simulations. Our analysis introduces a novel approach to generate initial conditions with significant parity asymmetry without changing the initial matter power spectrum. Focusing on the helicity of the initial spin and halo spin vector fields, we detect substantial parity asymmetry in the initial spin field, with over 50% of this asymmetry surviving in the late-time halo spin field across a range of scales. I will discuss the cosmological implications of our findings and conclude with future opportunities from upcoming galaxy surveys.