125 citations · 1.5k across the 62 of their papers we have counts for
32 papers · 1 filter
Attractive gravity probe surface with positive cosmological constant
Tetsuya Shiromizu, Keisuke Izumi
In four dimensional spacetimes with a positive cosmological constant, we introduce a new geometrical object associated with the cosmological horizon and then show the areal inequal…
Asymptotic behavior of null geodesics near future null infinity IV: Null-access theorem for generic asymptotically flat spacetime
Masaya Amo, Keisuke Izumi, Yoshimune Tomikawa +2
In our previous papers [arXiv:2106.03150, arXiv:2110.10917, arXiv:2208.00822], we analyzed the asymptotic behavior of future directed null geodesics near future null infinity and t…
A generalization of photon sphere based on escape/capture cone
Masaya Amo, Keisuke Izumi, Hirotaka Yoshino +2
In asymptotically flat spacetimes, bearing the null geodesics reaching the future null infinity in mind, we propose new concepts, the "dark horizons" as generalizations of the phot…
Attractive gravity probe surfaces in higher dimensions
Keisuke Izumi, Yoshimune Tomikawa, Tetsuya Shiromizu +1
A generalization of the Riemannian Penrose inequality in -dimensional space () is done. We introduce a parameter () indicating the streng…
Asymptotic behavior of null geodesics near future null infinity. III. Photons towards inward directions
Masaya Amo, Keisuke Izumi, Yoshimune Tomikawa +2
A new sufficient condition for photons emitted near future null infinity to reach future null infinity is derived by studying null geodesics in the Bondi coordinates in asymptotica…
Maximum size of black holes in our accelerating Universe
Tetsuya Shiromizu, Keisuke Izumi, Kangjae Lee +1
In accordance with current models of the accelerating Universe as a spacetime with a positive cosmological constant, new results about a cosmological upper bound for the area of st…