・Yasutaka Koga, Nobuyuki Asaka, Masashi Kimura, Kazumasa Okabayashi, "Shadow formation in gravitational collapse: redshift and blueshift by spacetime dynamics"

・Masazumi Honda, Hiroki Matsui, Kota Numajiri, Kazumasa Okabayashi, "Jackiw-Teitelboim Gravity and Lorentzian Quantum Cosmology"

・Kota Numajiri, Kazumasa Okabayashi, Shinji Mukohyama, "Boulware Vacuum vs. Regularity: Thoughts on Anomaly-Induced Effective Action"

・Kazumasa Okabayashi, Naritaka Oshita, "Greybody Factors Imprinted on Black Hole Ringdowns. II. Merging Binary Black Holes"

・Masazumi Honda, Hiroki Matsui, Kazumasa Okabayashi, Takahiro Terada, "Resurgence in Lorentzian quantum cosmology: No-boundary saddles and resummation of quantum gravity corrections around tunneling saddle points"

・Ken-ichi Nakao, Kazumasa Okabayashi, Tomohiro Harada, "Radiative gravastar with thermal spectrum; Sudden vacuum condensation without gravitational collapse"

・Ken-ichi Nakao, Kazumasa Okabayashi, Tomohiro Harada, "Radiative gravastar with Gibbons-Hawking temperature"

・Yasutaka Koga, Nobuyuki Asaka, Masashi Kimura, Kazumasa Okabayashi, "Dynamical photon sphere and time evolving shadow around black holes with temporal accretion"

・Kazumasa Okabayashi, Tomohiro Harada, Ken-ichi Nakao, "Robustness of particle creation in the formation of a compact object"

・Kazumasa Okabayashi, Nobuyuki Asaka, Ken-ichi Nakao, "Do black hole shadows merge?"

・Kazumasa Okabayashi, Kei-ichi Maeda, "Maximal Efficiency of Collisional Penrose Process with Spinning Particles II"

・Kei-ichi Maeda, Kazumasa Okabayashi, Hirotada Okawa, "Maximal Efficiency of Collisional Penrose Process with Spinning Particles"