Speaker
Description
Based on [arxiv:2412.16072] Recent observations from the James Webb Space Telescope revealed a surprisingly large number of galaxies formed at high redshift. Along with strong lensing studies and nearby galaxy observations, these could challenge the standard Lambda Cold Dark Matter cosmology with a power-law primordial power spectrum. In this study, we conduct high-resolution cosmological zoom-in dark matter-only simulations of Milky Way host size halos with a blue, tilted primordial power spectrum (P(k)∝k^m_s with m_s>1 at small scales >1 Mpc^{−1}). We find that the blue-tilted subhalo mass functions can be enhanced by more than a factor of two for subhalo masses Msub≲10^10 M⊙, whereas the subhalo Vmax functions can be enhanced by a factor of four for maximum circular velocities Vmax≲30 km/s. The blue-tilted scaled cumulative substructure fraction can be an order of magnitude higher at ∼10\% of the virial radius. The blue-tilted subhalos also have higher central densities, since the blue-tilted subhalos reach the same Vmax at a smaller distance Rmax from the center. We have also verified these findings with higher-resolution simulations.
