219 citations · 2.3k across the 55 of their papers we have counts for
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Scrutinizing black hole stability in cubic vector Galileon theories
Antonio De Felice, Ryotaro Kase, Shinji Tsujikawa
In a subclass of generalized Proca theories where a cubic vector Galileon term breaks the gauge invariance, it is known that there are static and spherically symmetric black…
Neutral particle collisions near Gibbons-Maeda-Garfinkle-Horowitz-Strominger black holes after shadow observations
Naoki Tsukamoto, Ryotaro Kase
A Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS) black hole with a magnetic charge (or an electric charge) has noteworthy features that its scalar curvature near the event hor…
Even-parity stability of hairy black holes in gauge-invariant scalar-vector-tensor theories
Chao Zhang, Ryotaro Kase
The gauge-invariant scalar-vector-tensor theories, which catches five degrees of freedom, are valuable for its implications to inflation problems, generation of primordial m…
Constraints on the black-hole charges of M87* and Sagittarius A* by changing rates of photon spheres can be relaxed
Naoki Tsukamoto, Ryotaro Kase
The Event Horizon Telescope (EHT) Collaboration observed ring images called the shadows of M87* and Sagittarius~A* (Sgr~A*), which are supermassive objects in M87 and our galaxy, r…
Hairy black holes in extended Einstein-Maxwell-scalar theories with magnetic charge and kinetic couplings
Kitaro Taniguchi, Shinta Takagishi, Ryotaro Kase
We study black hole (BH) solutions in extended Einstein-Maxwell-scalar theories, which are classified in a subclass of the gauge-invariant scalar-vector-tensor theories. The…