362 citations · 939 across the 46 of their papers we have counts for
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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…
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…
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…
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…
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…
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…
Dust Reverberation Mapping of Type 2 AGN NGC 2110 Realized with X-ray and 3-5 m IR monitoring
Hirofumi Noda, Taiki Kawamuro, Mitsuru Kokubo +1
The dust reverberation mapping is one of powerful methods to investigate the structure of the dusty tori in AGNs, and it has been performed on more than a hundred type 1 AGNs. Howe…
Properties of AGN Multiband Optical Variability in the HSC SSP Transient Survey
Yuki Kimura, Toru Yamada, Mitsuru Kokubo +4
We study variability of active galactic nuclei (AGNs) by using the deep optical multiband photometry data obtained from the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP) sur…
Dust Destruction by Charging: A Possible Origin of Grey Extinction Curves of Active Galactic Nuclei
Ryo Tazaki, Kohei Ichikawa, Mitsuru Kokubo
Observed extinction curves of active galactic nuclei (AGNs) are significantly different from those observed in the Milky Way. The observations require preferential removal of small…
Tracing the co-evolution path of super massive black holes and spheroids with AKARI-selected ultra-luminous IR galaxies at intermediate redshifts
Xiao-Yang Chen, Masayuki Akiyama, Kohei Ichikawa +6
We present the stellar population and ionized-gas outflow properties of ultra-luminous IR galaxies (ULIRGs) at 0.1-1.0, which are selected from AKARI FIR all-sky survey. We co…
Rapid Luminosity Decline and Subsequent Reformation of the Innermost Dust Distribution in the Changing-look AGN Mrk 590
Mitsuru Kokubo, Takeo Minezaki
We examine the long-term optical/near-infrared (NIR) flux variability of a "changing-look" active galactic nucleus (AGN) Mrk 590 between 1998 and 2007. Multi-band multi-epoch optic…
Discovery of a strong ionized-gas outflow in an AKARI-selected Ultra-luminous Infrared Galaxy at z = 0.5
Xiaoyang Chen, Masayuki Akiyama, Hirofumi Noda +6
In order to construct a sample of ultra-luminous infrared galaxies (ULIRGs, with infrared luminosity, L) at 0.5 < z < 1, we are conducting an optic…
Constraints on accretion disk size in the massive type 1 quasar PG 2308+098 from optical continuum reverberation lags
Mitsuru Kokubo
Two years' worth of u-, g-, r-, i-, and z-band optical light curves were obtained for the massive type 1 quasar PG 2308+098 at z=0.433 using the 1.05-m Kiso Schmidt telescope/Kiso…
OISTER Optical and Near-Infrared Monitoring Observations of a Peculiar Radio-Loud Active Galactic Nucleus SDSS J110006.07+442144.3
Tomoki Morokuma, Masaomi Tanaka, Yasuyuki T. Tanaka +80
We present monitoring campaign observations at optical and near-infrared (NIR) wavelengths for a radio-loud active galactic nucleus (AGN) at z=0.840, SDSS~J110006.07+442144.3 (here…
H intensity map of the repeating fast radio burst FRB 121102 host galaxy from Subaru/Kyoto 3DII AO-assisted optical integral-field spectroscopy
Mitsuru Kokubo, Kazuma Mitsuda, Hajime Sugai +8
We present the H intensity map of the host galaxy of the repeating fast radio burst FRB 121102 at a redshift of z=0.193 obtained with the AO-assisted Kyoto 3DII optical integral…
Constraints on the optical polarization source in the luminous non-blazar quasar 3C 323.1 (PG 1545+210) from the photometric and polarimetric variability
Mitsuru Kokubo
We examine the optical photometric and polarimetric variability of the luminous type 1 non-blazar quasar 3C 323.1 (PG 1545+210). Two optical spectro-polarimetric measurements taken…
X-ray and Optical Correlation of Type I Seyfert NGC 3516 Studied with Suzaku and Japanese Ground-Based Telescopes
Hirofumi Noda, Takeo Minezaki, Makoto Watanabe +23
From 2013 April to 2014 April, we performed an X-ray and optical simultaneous monitoring of the type 1.5 Seyfert galaxy NGC 3516. It employed Suzaku, and 5 Japanese ground-based te…
The relationship between variable and polarized optical spectral components of luminous type 1 non-blazar quasars
Mitsuru Kokubo
Optical spectropolarimetry carried out by Kishimoto et al. (2004) has shown that several luminous type 1 quasars show a strong decrease of the polarized continuum flux in the rest-…
An Effective Selection Method for Low-Mass Active Black Holes and First Spectroscopic Identification
Tomoki Morokuma, Nozomu Tominaga, Masaomi Tanaka +13
We present a new method to effectively select objects which may be low-mass active black holes (BHs) at galaxy centers using high-cadence optical imaging data, and our first spectr…