日時 : 2020年12月1日(火) 16:30～
場所 : F205（理学部F棟 第4講義室）
題目 : Modeling evolution of dark matter substructure and annihilation boost
講演者 : 広島 渚 (富山大)
概要 : We study evolution of dark matter substructures, especially how they lose the mass and change density profile after they fall in gravitational potential of larger host halos. We develop an analytical prescription that models the subhalo mass evolution and calibrate it to results of N-body numerical simulations of various scales from very small (Earth size) to large (galaxies to clusters) halos. We then combine the results with halo accretion histories, and calculate the subhalo mass function that is physically motivated down to Earth-mass scales. Our results --- valid for arbitrary host masses and redshifts --- show reasonable agreement with those of numerical simulations at resolved scales. Our analytical model also enables self-consistent calculations of the boost factor of dark matter annihilation, which we find to increase from tens of percent at the smallest (Earth) and intermediate (dwarfs) masses to a factor of several at galaxy size, and to become as large as a factor of ∼10 for the largest halos (clusters) at small redshifts. The effects of the boost on the WIMP search using isotropic gamma-ray background observations are also discussed.