23 citations · 33 across the 14 of their papers we have counts for
16 papers
Simulation of PBH formation in a matter-dominated universe
Chul-Moon Yoo, Albert Escrivà, Tomohiro Harada +1
We investigate primordial black hole (PBH) formation during an early matter-dominated era using fully nonlinear numerical relativity. The initial condition is set by a functional f…
Discrete self-similarity imprints on primordial-black-hole mass functions
Luis E. Padilla, Tomohiro Harada, Hayami Iizuka
We study how discrete self-similarity (DSS) in the critical behavior of scalar-field collapse is imprinted on primordial-black-hole (PBH) mass functions. Using the DSS-modulated cr…
Determining Kerr black hole spin and inclination from a segment of the critical curve in black hole images
Kenta Hioki, Umpei Miyamoto, Tomohiro Harada
We present a method for determining the spin parameter and inclination angle of a non-extremal Kerr black hole from segments of the critical curve identified in black hol…
COSMOS: A numerical relativity code specialized for PBH formation
Chul-Moon Yoo, Hirotada Okawa, Albert Escrivà +7
Primordial black holes (PBHs) are black holes generated in the early universe without having gone through stellar evolution. In the standard formation process, PBHs are formed from…
Supermassive black hole seeds from direct collapse of CDM-curvature peaks
Marco Galoppo, Marco Bruni, Tomohiro Harada
We study black hole (BH) formation from the nonlinear growth and collapse of primordial perturbations during the matter-dominated era. Modelling cold dark matter (CDM) as pressurel…
Gravitational wave emission from nonspherical collapse in an early matter-dominated era using N-body simulations
Albert Escrivà, Tomohiro Harada, Kazunori Kohri +2
We study the dynamics of the collapse of a nonspherical overdense patch during an early matter-dominated era and the associated production of gravitational waves (GWs) using a semi…
Cosmological discrete self-similarity in primordial black hole formation
Luis E. Padilla, Tomohiro Harada, Ethan Milligan +1
We demonstrate that discrete self-similarity (DSS), originally discovered in the collapse of a massless scalar field in an asymptotically flat system, survives in primordial black…
Primordial Black Hole Formation and Spin in Matter Domination Revisited
Weitao Ye, Yungui Gong, Tomohiro Harada +4
In this article, we calculate the mass distribution of primordial black holes (PBHs) formed in the matter-dominated (MD) era by the peak theory. We apply the Zel'dovich approximati…
Primordial black hole formation from a type II perturbation in the absence and presence of pressure
Koichiro Uehara, Albert Escrivà, Tomohiro Harada +2
We investigate primordial black holes (PBHs) formed from extremely large amplitudes of primordial curvature fluctuations, classified as type II. Type II fluctuations differ from ty…
General relativistic effects on photon spectrum emitted from dark matter halos around primordial black holes
Toya Suzuki, Takahisa Igata, Kazunori Kohri +1
We investigate general relativistic effects on the photon spectrum emitted from decaying (or annihilating) particle dark matter in the halo surrounding a primordial black hole. The…
Geometrical origin for the compaction function for primordial black hole formation
Tomohiro Harada, Hayami Iizuka, Yasutaka Koga +1
We propose a geometrical origin for the Shibata-Sasaki compaction function, which is known to be a reliable indicator of primordial black hole formation at least during radiation d…
Revisiting spins of primordial black holes in a matter-dominated era based on peak theory
Daiki Saito, Tomohiro Harada, Yasutaka Koga +1
We estimate the probability distribution for the spins of the primordial black holes (PBHs) that formed during an early matter-dominated era in the Universe. We employ the Zel'dovi…
New series expansion method for the periapsis shift
Akihito Katsumata, Tomohiro Harada, Kota Ogasawara +1
We propose a new series expansion method for the periapsis shift. The method formulates the periapsis shift in various spacetimes analytically without using special functions and p…
Numerical simulation of type II primordial black hole formation
Koichiro Uehara, Albert Escrivà, Tomohiro Harada +2
This study investigates the formation of type II primordial black holes (PBHs) resulting from extremely large amplitudes of initial fluctuations in a radiation-dominated universe.…
Current status of space gravitational wave antenna DECIGO and B-DECIGO
Seiji Kawamura, Masaki Ando, Naoki Seto +84
Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) is the future Japanese space mission with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at the detection of pri…
Relativistic Gravitational Collapse of a Cylindrical Shell of Dust
Ken-ichi Nakao, Yasunari Kurita, Yoshiyuki Morisawa +1
The gravitational collapse of a thick cylindrical shell of dust matter is investigated. It is found that a spacetime singularity forms on the symmetry axis and that it is necessari…