106 citations · 306 across the 8 of their papers we have counts for
7 papers · 1 filter
Constraints on Primordial Black Holes by Distortions of Cosmic Microwave Background
Hiroyuki Tashiro, Naoshi Sugiyama
Possible influence of primordial black hole (PBH) evaporations on cosmic microwave background (CMB) is investigated. The spectrum distortions of CMB from the black-body spectrum ar…
Electromagnetic Properties of the Early Universe
Keitaro Takahashi, Kiyotomo Ichiki, Naoshi Sugiyama
Detailed physical processes of magnetic field generation from density fluctuations in the pre-recombination era are studied. Solving Maxwell equations and the generalized Ohm's law…
Magnetic Field Spectrum at Cosmological Recombination
Kiyotomo Ichiki, Keitaro Takahashi, Naoshi Sugiyama +2
A generation of magnetic fields from cosmological density perturbations is investigated. In the primordial plasma before cosmological recombination, all of the materials except dar…
Hard X-ray and Gamma-ray Emission Induced by Ultra-High Energy Protons in Cluster Accretion Shocks and their Detectability
Susumu Inoue, Felix A. Aharonian, Naoshi Sugiyama
Protons can be plausibly accelerated to - eV in strong accretion shocks surrounding massive clusters of galaxies. Such protons efficiently produce very high…
Gravitational Radiation from Coalescing Supermassive Black Hole Binaries in a Hierarchical Galaxy Formation Model
Motohiro Enoki, Kaiki T. Inoue, Masahiro Nagashima +1
We investigate the expected gravitational wave emission from coalescing supermassive black hole (SMBH) binaries resulting from mergers of their host galaxies. We employ a semi-anal…
Double Inflation in Supergravity and the Boomerang Observations
Toshiyuki Kanazawa, Masahiro Kawasaki, Naoshi Sugiyama +1
One of the biggest mystery of the recent observation of cosmic microwave background anisotropies by the boomerang team is insignificance of the second acoustic peak in the angular…