152 citations · 1.9k across the 51 of their papers we have counts for
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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…
Constraining the primordial curvature perturbation using dark matter substructure
Shin'ichiro Ando, Nagisa Hiroshima, Koji Ishiwata
We investigate the primordial curvature perturbation by the observation of dark matter substructure. Assuming a bump in the spectrum of the curvature perturbation in the wavenumber…
Sommerfeld-enhanced dark matter searches with dwarf spheroidal galaxies
Shin'ichiro Ando, Koji Ishiwata
We study observable signals from dark matter that self-annihilates via the Sommerfeld effect in dwarf spheroidal galaxies (dSphs). Since the effect of the Sommerfeld enhancement de…
Superconformal Subcritical Hybrid Inflation
Koji Ishiwata
We consider D-term hybrid inflation in the framework of superconformal supergravity. In part of the parameter space, inflation continues for subcritical inflaton field value. Conse…
Constraints on decaying dark matter from the extragalactic gamma-ray background
Shin'ichiro Ando, Koji Ishiwata
If dark matter is unstable and the mass is within GeV-TeV regime, its decays produce high-energy photons that give contribution to the extragalactic gamma-ray background (EGRB). We…
Cosmic Gamma-ray from Inverse Compton Process in Unstable Dark Matter Scenario
Koji Ishiwata, Shigeki Matsumoto, Takeo Moroi
Motivated by the PAMELA anomaly in the fluxes of cosmic-ray electron and positron, we study the cosmic gamma-ray induced by the inverse Compton (IC) scattering process in unstable…