activity
20242026
collaborators

5 papers

astro-ph.CO2026

Primordial tensor mode from the neutrino sector

Shohei Saga, Shuichiro Yokoyama

We show that a regular solution for primordial tensor fluctuations can arise from the higher-order multipoles of the collisionless neutrino distribution after neutrino decoupling.…

astro-ph.CO2026

Revisiting constraints on primordial vector modes and implications for sourced magnetic fields and observed power spectrum

Kaito Yura, Shohei Saga, Shuichiro Yokoyama +1

We revisit regular primordial vector modes sustained by the anisotropic stress of free-streaming neutrinos. We consider two classes of neutrino-sector initial conditions, the neutr…

astro-ph.CO2025

Parity-violating scalar trispectrum from helical primordial magnetic fields

Kaito Yura, Shohei Saga, Maresuke Shiraishi +1

Some recent observations of the cosmic microwave background (CMB) anisotropies and the large-scale structure of the Universe imply cosmic parity violation. Among possible parity-vi…

astro-ph.CO2025

Shapes and orientations of massive halos in the statistically anisotropic universe

Shogo Masaki, Yurino Mizuguchi, Shohei Saga +1

We investigate how statistical anisotropy (SA) in matter distributions affects the distributions of shapes and orientations of cluster-sized halos, using cosmological -body simu…

astro-ph.CO2024

First confirmation of anisotropic halo bias from statistically anisotropic matter distributions

Shogo Masaki, Maresuke Shiraishi, Takahiro Nishimichi +2

We confirm for the first time the existence of distinctive halo bias associated with the quadrupolar type of statistical anisotropy (SA) of the linear matter density field using co…