251 citations · 2.2k across the 40 of their papers we have counts for
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gr-qc2012★ 60 cited
Signed magnification sums for general spherical lenses
Naoki Tsukamoto, Tomohiro Harada
It is well known that the sum of signed magnifications is invariant for mass lens systems. In this paper, we discuss the signed magnification sums of general spherical lens models…
gr-qc2012★ 224 cited
Can we distinguish between black holes and wormholes by their Einstein-ring systems?
Naoki Tsukamoto, Tomohiro Harada, Kohji Yajima
For the last decade, the gravitational lensing in the strong gravitational field has been studied eagerly. It is well known that, for the lensing by a black hole, infinite number o…
gr-qc2012★ 4 cited
A No-Go Theorem for Rotating Stars of a Perfect Fluid without Radial Motion in Projectable Hořava--Lifshitz Gravity
Naoki Tsukamoto, Tomohiro Harada
Hořava--Lifshitz gravity has covariance only under the foliation-preserving diffeomorphism. This implies that the quantities on the constant-time hypersurfaces should be regular. I…