66 citations · 529 across the 24 of their papers we have counts for
24 papers
A unified treatment of the redshift, the Doppler effect, and the time dilation in general relativity
Masumi Kasai
We present a unified treatment of the gravitational and cosmological redshift, the Doppler effect due to the moving observer or light source, and the time dilation in the gravitati…
The gauge-invariant formulation of the local expansion rate driven by the local average density in an inhomogeneous universe
Masanori Tomonaga, Masumi Kasai, Toshifumi Futamase
The Hubble tension casts a blight on the standard cosmology. As a possible solution to the problem, the local variation of the expansion rate has been proposed where the spatial av…
A possible solution to the Hubble constant discrepancy -- Cosmology where the local volume expansion is driven by the domain average density
Masumi Kasai, Toshifumi Futamase
The Hubble constant problem is the discrepancy between different measurements of the Hubble constant in different scales. We show that this problem can be resolved within the gener…
An analytical approximation of the luminosity distance in flat cosmologies with a cosmological constant
Masaru Adachi, Masumi Kasai
We present an analytical approximation formula for the luminosity distance in spatially flat cosmologies with dust and a cosmological constant. Apart from the overall factor, the e…
Effect of the cosmological constant on the bending of light and the cosmological lens equation
Hideyoshi Arakida, Masumi Kasai
We revisit the effect of cosmological constant on the light deflection and its role in the cosmological lens equation. First, we re-examine the motion of photon in the Schwarzs…
Perturbative Approach to the Gravitational Lensing by a Non-spherically Distorted Compact Object
Amano Saijo, Masumi Kasai
We investigate the gravitational lens effect caused by a non-spherically distorted compact object. The non-spherical property of the gravitational potential is modeled by a quadrup…