10 citations · 11 across the 5 of their papers we have counts for
6 papers
Exploring the Primordial Power Spectrum with Dark-Age 21 cm fluctuations
Fumiya Okamatsu, Tomo Takahashi, Shuichiro Yokoyama
We investigate the potential of future observations of the Dark Ages 21 cm power spectrum to probe the scale dependence of the primordial power spectrum and distinguish between inf…
Detectability and Template Distinguishability of the Dark Ages 21 cm Global Signal with Wide and Sparse Frequency Coverage
Shintaro Yoshiura, Fumiya Okamatsu, Tomo Takahashi
The Dark Ages 21cm signal, observed at frequencies below 50 MHz, can serve as a powerful probe of cosmology, as the standard cosmological model predicts a well-defined 21cm spectra…
Super-critical primordial black hole formation via delayed first-order electroweak phase transition
Katsuya Hashino, Shinya Kanemura, Tomo Takahashi +2
The delay of the first-order electroweak phase transitions (EWPT) may lead to the emergence of baby universes inside wormhole structures due to the large vacuum energy density in f…
Kurtosis consistency relation in large-scale structure as a probe of gravity theories
Sora Yamashita, Takahiko Matsubara, Tomo Takahashi +1
Various gravity theories beyond general relativity have been rigorously investigated in the literature such as Horndeski and degenerate higher-order scalar-tensor (DHOST) theories.…
Constraints on sterile neutrinos and the cosmological tensions
Supriya Pan, Osamu Seto, Tomo Takahashi +1
We investigate cosmological bounds on sterile neutrino masses in the light of the Hubble and tensions. We argue that non-zero masses for sterile neutrinos are inferred at 2$σ…
Dark age consistency in the 21cm global signal
Fumiya Okamatsu, Teppie Minoda, Tomo Takahashi +2
We propose a new observable for the 21cm global signal during the dark ages, the dark-age consistency ratio, which is motivated from the fact that the shape of the functional form…