66 citations · 99 across the 4 of their papers we have counts for
5 papers · 1 filter
Toward a No-Go Theorem for an Accelerating Universe through a Nonlinear Backreaction
Masumi Kasai, Hideki Asada, Toshifumi Futamase
The backreaction of nonlinear inhomogeneities to the cosmic expansion is re-analyzed in the framework of general relativity. Apparent discrepancies regarding the effect of the nonl…
Euclidean Algorithm for a Gravitational Lens in a Polynomial Equation
Hideki Asada, Taketoshi Kasai, Masumi Kasai
The Euclidean algorithm in algebra is applied to a class of gravitational lenses for which the lens equation consists of any set of coupled polynomial equations in the image positi…
Separability of Rotational Effects on a Gravitational Lens
Hideki Asada, Masumi Kasai, Tatsuya Yamamoto
We derive the deflection angle up to due to a Kerr gravitational lens with mass and specific angular momentum . It is known that at the linear order in and …
Algebraic Properties of the Real Quintic Equation for a Binary Gravitational Lens
Hideki Asada, Taketoshi Kasai, Masumi Kasai
It has been recently shown that the lens equation for a binary gravitational lens, which is apparently a coupled system, can be reduced to a real fifth-order (quintic) algebraic eq…
Images for an Isothermal Ellipsoidal Gravitational Lens from a Single Real Algebraic Equation
Hideki Asada, Takashi Hamana, Masumi Kasai
We present explicit expressions for the lens equation for a cored isothermal ellipsoidal gravitational lens as a single real sixth-order algebraic equation in two approaches; 2-dim…