collaborators

7 papers

astro-ph.CO2026

A lower bound on primordial power spectrum from halo substructure

Shin'ichiro Ando, Nagisa Hiroshima, Koji Ishiwata +1

We investigate how the primordial curvature perturbation of a certain wavelength scale affects the halo and subhalo structure. Primordial power spectrum considered in this paper fe…

astro-ph.CO2026

Wave-optics imprints of dark matter subhalos on strongly lensed gravitational waves. II. Saddle images and detectability

Shin'ichiro Ando

Wave-optics interference in strongly lensed gravitational waves is a new interferometric probe of dark matter substructure: a subhalo population threading a galaxy-scale lens impri…

astro-ph.CO2026

Wave-Optics Imprints of Dark Matter Subhalos on Strongly Lensed Gravitational Waves

Shin'ichiro Ando

Wave-optics effects in strongly lensed gravitational waves (GWs) provide a new interferometric probe of dark matter substructure. We compute the full diffraction integral for GWs p…

astro-ph.CO2025

Supermassive black holes from inflation constrained by dark matter substructure

Shin'ichiro Ando, Shyam Balaji, Malcolm Fairbairn +2

Recent James Webb Space Telescope observations of high-redshift massive galaxy candidates have initiated renewed interest in the important mystery around the formation and evolutio…

astro-ph.CO2025

Comparison of simulations and semi-analytical model for WDM subhalo mass functions

Mizuki Ono, Takashi Okamoto, Shin'ichiro Ando +1

The Cold Dark Matter (CDM) model successfully explains large-scale structure formation, but challenges remain at smaller scales, leading to interest in Warm Dark Matter (WDM) as an…

astro-ph.CO2025

Stringent Constraints on Self-Interacting Dark Matter Using Milky-Way Satellite Galaxies Kinematics

Shin'ichiro Ando, Kohei Hayashi, Shunichi Horigome +2

Self-interacting dark matter (SIDM) has been proposed to address small-scale challenges faced by the cold dark matter (CDM) paradigm, such as the diverse density profiles observed…