683 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Tohoku UniversityJP202 papers
- The University of TokyoJP78 papers
- Kyoto UniversityJP59 papers
- National Astronomical Observatory of JapanJP44 papers
- Kavli Institute for the Physics and Mathematics of the UniverseJP40 papers
- Nagoya UniversityJP33 papers
- The University of OsakaJP32 papers
- Massachusetts Institute of TechnologyUS30 papers
- Institute of Space and Astronautical ScienceJP27 papers
- Japan Aerospace Exploration AgencyJP26 papers
- Ehime UniversityJP24 papers
- Institute of Astronomy and Astrophysics, Academia SinicaTW24 papers
30 papers · 1 filter
BASS XXIX: The near-infrared view of the BLR: the effects of obscuration in BLR characterisation
Ricci F., Treister E., Bauer F. E. +24
Virial black hole mass () determination directly involves knowing the broad line region (BLR) clouds velocity distribution, their distance from the central supermassive bla…
Non-thermally trapped inflation by tachyonic dark photon production
Naoya Kitajima, Shota Nakagawa, Fuminobu Takahashi
We show that a dark Higgs field charged under U(1) gauge symmetry is trapped at the origin for a long time, if dark photons are produced by an axion condensate via tachyo…
The Variability of the Black-Hole Image in M87 at the Dynamical Time Scale
Kaushik Satapathy, Dimitrios Psaltis, Feryal Ozel +235
The black-hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center o…
Candidate Tidal Disruption Event AT2019fdr Coincident with a High-Energy Neutrino
Simeon Reusch, Robert Stein, Marek Kowalski +46
The origins of the high-energy cosmic neutrino flux remain largely unknown. Recently, one high-energy neutrino was associated with a tidal disruption event (TDE). Here we present A…
New scenario of QCD axion clump formation I: Linear analysis
Naoya Kitajima, Kazuhiro Kogai, Yuko Urakawa
The QCD axion acquires the potential through the non-perturbative effect of the QCD matters around the QCD phase transition. During this period, the direct interaction between the…
Primordial black holes in peak theory with a non-Gaussian tail
Naoya Kitajima, Yuichiro Tada, Shuichiro Yokoyama +1
In this paper, we update the peak theory for the estimation of the primordial black hole (PBH) abundance, particularly by implementing the critical behavior in the estimation of th…
Energy partition between Alfvénic and compressive fluctuations in magnetorotational turbulence with near-azimuthal mean magnetic field
Y. Kawazura, A. A. Schekochihin, M. Barnes +2
The theory of magnetohydrodynamic (MHD) turbulence predicts that Alfvénic and slow-mode-like compressive fluctuations are energetically decoupled at small scales in the inertial ra…
Unstable diffusion in social networks
Teruyoshi Kobayashi, Yoshitaka Ogisu, Tomokatsu Onaga
How and to what extent will new activities spread through social ties? Here, we develop a more sophisticated framework than the standard mean-field approach to describe the diffusi…
Hypercubes of AGN Tori (HYPERCAT) -- II. Resolving the Torus with Extremely Large Telescopes
R. Nikutta, E. Lopez-Rodriguez, K. Ichikawa +4
Recent infrared interferometric observations revealed sub-parsec scale dust distributions around active galactic nuclei (AGNs). Using images of CLUMPY torus models and NGC 1068 as…
Multi-frequency radio observations of the radio-loud magnetar XTE J1810-197
Sujin Eie, Toshio Terasawa, Takuya Akahori +11
We report on the multi-frequency multi-epoch radio observations of the magnetar, XTE J1810-197, which exhibited a radio outburst from December 2018 after its 10-year quiescent peri…
Semiclassical analysis of axion-assisted and axion-driven pair production
Hiroyuki Kitamoto, Masaki Yamada
We study the pair production of fermions in a time dependent axion background with and without an electric background. We construct the adiabatic mode functions which incorporate t…
Multi-wavelength emission from magnetically arrested disks around isolated black holes
Shigeo S. Kimura, Kazumi Kashiyama, Kenta Hotokezaka
We discuss the prospects for identifying nearest isolated black holes (IBHs) in our Galaxy. IBHs accreting gas from the interstellar medium (ISM) likely form magnetically arrested…
A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). IV. Rapidly Growing (Super-)Massive Black Holes in Extremely Radio-Loud Galaxies
Kohei Ichikawa, Takuji Yamashita, Yoshiki Toba +19
We present the optical and infrared properties of 39 extremely radio-loud galaxies discovered by cross-matching the Subaru/Hyper Suprime-Cam (HSC) deep optical imaging survey and V…
Limits on astrophysical antineutrinos with the KamLAND experiment
S. Abe, S. Asami, A. Gando +66
We report on a search for electron antineutrinos () from astrophysical sources in the neutrino energy range 8.3 to 30.8 MeV with the KamLAND detector. In an exposure of 6.…
The response of black hole spark gaps to external changes: A production mechanism of rapid TeV flares?
Shota Kisaka, Amir Levinson, Kenji Toma +1
We study the response of a starved Kerr black hole magnetosphere to abrupt changes in the intensity of disk emission and in the global magnetospheric current, by means of 1D genera…
The eROSITA Final Equatorial-Depth Survey (eFEDS): The AGN Catalogue and its X-ray Spectral Properties
Teng Liu, Johannes Buchner, Kirpal Nandra +23
Context: After the successful launch of the Spectrum-Roentgen-Gamma (SRG) mission in July 2019, eROSITA, the soft X-ray instrument aboard SRG, performed scanning observations of a…
The eROSITA Final Equatorial-Depth Survey (eFEDS): A multiwavelength view of WISE mid-infrared galaxies/active galactic nuclei
Yoshiki Toba, Teng Liu, Tanya Urrutia +21
We investigate the physical properties--such as the stellar mass, SFR, IR luminosity, X-ray luminosity, and hydrogen column density--of MIR galaxies and AGN at in the 140 d…
The eROSITA Final Equatorial-Depth Survey (eFEDS): Identification and characterization of the counterparts to the point-like sources
M. Salvato, J. Wolf, T. Dwelly +41
In November 2019, eROSITA on board of SRG observatory started to map the entire sky in X-rays. After the 4-year survey program, it will reach flux limits about 25 times deeper than…
Optical Spectroscopy of Dual Quasar Candidates from the Subaru HSC-SSP program
Shenli Tang, John D. Silverman, Xuheng Ding +30
We report on a spectroscopic program to search for dual quasars using Subaru Hyper Suprime-Cam (HSC) images of SDSS quasars which represent an important stage during galaxy mergers…
The Polarized Image of a Synchrotron Emitting Ring of Gas Orbiting a Black Hole
Ramesh Narayan, Daniel C. M. Palumbo, Michael D. Johnson +237
Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field i…
First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
The Event Horizon Telescope Collaboration
Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotr…
First M87 Event Horizon Telescope Results. VII. Polarization of the Ring
The Event Horizon Telescope Collaboration
In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observat…
Backreaction of Mass and Angular Momentum Accretion on Black Holes: General Formulation of the Metric Perturbations and Application to the Blandford-Znajek Process
Masashi Kimura, Tomohiro Harada, Atsushi Naruko +1
We study the metric backreaction of mass and angular momentum accretion on black holes. We first develop the formalism of monopole and dipole linear gravitational perturbations aro…
Search for Solar Flare Neutrinos with the KamLAND detector
S. Abe, S. Asami, A. Gando +65
We report the result of a search for neutrinos in coincidence with solar flares from the GOES flare database. The search was performed on a 10.8 kton-year exposure of KamLAND colle…