362 citations · 939 across the 46 of their papers we have counts for
46 papers
Discovery of four Narrow-line Type-1 Quasars at z = 2.54 -- 6.06 with Subaru 'Onohi'ula PFS-SSP
Ayumi Takahashi, Yoshiki Matsuoka, Yoshiki Toba +21
We report the discovery of four narrow-line type-1 quasars (NLQ1s) from the Subaru 'Onohi'ula Prime Focus Spectrograph Subaru Strategic Program (PFS-SSP). To extend a comprehensive…
Diverse Origins of Broad H Lines in Heavily Obscured AGNs Revealed by Multi-epoch Spectroscopy
Shoichiro Mizukoshi, Takeo Minezaki, Subaru Ubukata +8
According to the classical AGN model, broad emission lines originate from the broad-line region (BLR) and are observable only when the attenuation by the dusty torus is small. Howe…
Multiband Optical Photometric and Spectroscopic Monitoring of the 2024 Flare Event in Transition Blazar OP313
TianFang Zhang, Mitsuru Kokubo, Mamoru Doi +19
Blazars are active galactic nuclei known for their extreme variability, offering unique opportunities to study jet physics and high-energy emission mechanisms. In 2024, the Flat Sp…
Second-timescale Glints from Satellites and Space Debris Detected with Tomo-e Gozen
Masaomi Tanaka, Ichiro Takahashi, Naoki Yoshida +17
A search for second-timescale optical transients is one of the frontiers of time-domain astronomy. However, it has been pointed out that reflections of sunlight from Earth-orbiting…
A Joint Search for the Electromagnetic Counterpart to the Gravitational-Wave Binary Black-Hole Merger Candidate S250328ae with the Dark Energy Camera and the Prime Focus Spectrograph
Haibin Zhang, Mitsuru Kokubo, Sean MacBride +20
The first detection of an optical counterpart to a gravitational wave signal revealed that collaborative efforts between instruments with different specializations provide a unique…
A systematic search for rapid transients in the Subaru HSC-SSP transient survey
Seiji Toshikage, Masaomi Tanaka, Naoki Yasuda +9
Recent high-cadence transient surveys have discovered rapid transients whose light curve timescales are shorter than those of typical supernovae. In this paper, we present a system…
Implication of a galaxy-scale negative feedback by one of the most powerful multi-phase outflows in a hyper-luminous infrared galaxy at the intermediate redshift
Xiaoyang Chen, Masayuki Akiyama, Kohei Ichikawa +12
Powerful, galactic outflows driven by Active Galactic Nuclei (AGNs) are commonly considered as a main mechanism to regulate star formation in massive galaxies. Ultra- and hyper-lum…
Challenging the AGN scenario for JWST/NIRSpec LRD and non-LRD broad H emitters in light of non-detection of NIRCam photometric variability and X-ray
Mitsuru Kokubo, Yuichi Harikane
JWST has uncovered a substantial population of high- () galaxies exhibiting broad H emission line with a Full Width at Half Maximum exceeding 1,000 km/s. This po…
Updated Picture of the Active Galactic Nuclei with Dusty/Dust-free Gas Structures and Effects of the Radiation Pressure
Shoichiro Mizukoshi, Takeo Minezaki, Hiroaki Sameshima +5
This study investigates the properties of two gas structures of X-ray selected active galactic nuclei (AGNs), that is, dusty and dust-free gas components, by separating them with t…
Optical Variability of Blazars in the Tomo-e Gozen Northern Sky Transient Survey
TianFang Zhang, Mamoru Doi, Mitsuru Kokubo +14
We studied the optical variability of 241 BL Lacs and 83 flat-spectrum radio quasars (FSRQ) from the 4LAC catalog using data from the Tomo-e Gozen Northern Sky Transient Survey, wi…
X-ray Winds In Nearby-to-distant Galaxies (X-WING) - I: Legacy Surveys of Galaxies with Ultrafast Outflows and Warm Absorbers in -
Satoshi Yamada, Taiki Kawamuro, Misaki Mizumoto +10
As an inaugural investigation under the X-ray Winds In Nearby-to-distant Galaxies (X-WING) program, we assembled a dataset comprising 132 active galactic nuclei (AGNs) spanning red…
The relationship of SMBHs and host galaxies at in the deep optical variability-selected AGN sample in the COSMOS field
Atsushi Hoshi, Toru Yamada, Mitsuru Kokubo +2
We present the study on the relationship between SMBHs and their host galaxies using our variability-selected AGN sample () constructed from t…
Rayleigh and Raman scattering cross-sections and phase matrices of the ground-state hydrogen atom, and their astrophysical implications
Mitsuru Kokubo
We present explicit expressions for Rayleigh and Raman scattering cross-sections and phase matrices of the ground state hydrogen atom based on the Kramers-Heisenberg dispersio…
Near-infrared Variability Detected in the Young Star-Forming Dwarf Galaxy SBS 0335-052E
Shun Hatano, Mitsuru Kokubo, Masami Ouchi +17
SBS~0335-052E is a young star-forming dwarf galaxy with a total stellar mass of and an extremely low metallicity (), which…
eROSITA Final Equatorial-Depth Survey (eFEDS): eFEDS X-ray view of WERGS Radio Galaxies selected by the Subaru/HSC and VLA/FIRST survey
Kohei Ichikawa, Takuji Yamashita, Andrea Merloni +19
We construct the eROSITA X-ray catalog of radio galaxies discovered by the WERGS survey that is made by the cross-matching of the wide-area Subaru/HSC optical survey and VLA/FIRST…
Narrow Fe-K Reverberation Mapping Unveils the Deactivated Broad-Line Region in a Changing-Look Active Galactic Nucleus
Hirofumi Noda, Taisei Mineta, Takeo Minezaki +11
"Changing-look active galactic nuclei" (CLAGNs) are known to change their apparent types between types 1 and 2, usually accompanied by a drastic change in their luminosity on times…
H1821+643: The most X-ray and infrared luminous AGN in the Swift/BAT survey in the process of rapid stellar and supermassive black hole mass assembly
Hikaru Fukuchi, Kohei Ichikawa, Masayuki Akiyama +6
H1821+643 is the most X-ray luminous non-beamed AGN of erg s in the Swift/BAT ultra-hard X-ray survey and it is also a hyper-lumin…
Measurement of AGN dust extinction based on the near-infrared flux variability of WISE data
Shoichiro Mizukoshi, Takeo Minezaki, Shoichi Tsunetsugu +4
We present the measurement of the line-of-sight extinction of the dusty torus for a large number of obscured active galactic nuclei (AGNs) based on the reddening of the colour of t…
Finding of a population of active galactic nuclei showing a significant luminosity decline in the past yrs
J. Pflugradt, K. Ichikawa, M. Akiyama +4
Recent observations have revealed an interesting active galactic nuclei (AGN) subclass that shows strong activity at large scales ( kpc) but weaker at small scales ( pc…
MUSSES2020J: The Earliest Discovery of a Fast Blue Ultraluminous Transient at Redshift 1.063
Ji-an Jiang, Naoki Yasuda, Keiichi Maeda +22
In this Letter, we report the discovery of an ultraluminous fast-evolving transient in rest-frame UV wavelengths, MUSSES2020J, soon after its occurrence by using the Hyper Suprime-…
Third Data Release of the Hyper Suprime-Cam Subaru Strategic Program
Hiroaki Aihara, Yusra AlSayyad, Makoto Ando +64
The paper presents the third data release of Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), a wide-field multi-band imaging survey with the Subaru 8.2m telescope. HSC-SSP ha…
Reverberation Mapping of Two Luminous Quasars: the Broad-line Region Structure and Black Hole Mass
Sha-Sha Li, Sen Yang, Zi-Xu Yang +21
We report the results of a multi-year spectroscopic and photometric monitoring campaign of two luminous quasars, PG~0923+201 and PG~1001+291, both located at the high-luminosity en…
Multiple giant eruptions and X-ray emission in the recoiling AGN/LBV candidate SDSS1133
Mitsuru Kokubo
We present a comprehensive analysis of 20 years worth of multi-color photometric light curves, multi-epoch optical spectra, and X-ray data of an off-nuclear variable object SDSS113…
Constraints on the rate of supernovae lasting for more than a year from Subaru/Hyper Suprime-Cam
Takashi J. Moriya, Ji-an Jiang, Naoki Yasuda +15
Some supernovae such as pair-instability supernovae are predicted to have the duration of more than a year in the observer frame. To constrain the rates of supernovae lasting for m…