67 citations · 221 across the 18 of their papers we have counts for
18 papers
Blackbody Quasar and Radio Source (BBQSORS): A Candidate of Transitional Little Red Dots with a Blackbody Spectrum
Yuxing Zhong, Xiaoyang Chen, Kohei Ichikawa +12
We report Subaru/PFS spectroscopic follow-up of a radio-loud quasar at from the UNVEIL radio AGN catalog and with X-ray detections. The PFS spectrum displays a broad MgII…
A Wide and Deep Exploration of Radio-detected Active Galactic Nuclei with Subaru HSC (WERGS). XIII. High-z Radio Quasar Selection from HSC--VLASS over deg
Youwen Kong, Kohei Ichikawa, Hisakazu Uchiyama +12
We report the results of , , , and dropout selections based on optical identifications of Very Large Array Sky Survey (VLASS) radio sources using the Hyper Suprime-…
A Wide and Deep Exploration of Radio-detected Active Galactic Nuclei with Subaru HSC (WERGS). XII. Final Optical Identification of VLASS Radio Sources from the Subaru/HSC-SSP Wide Survey Over 1200 deg
Hisakazu Uchiyama, Kohei Ichikawa, Youwen Kong +11
We present a wide-area and deep optical identification catalog for radio sources based on the VLASS Epoch 2 catalog at 3 GHz. Optical counterparts are identified using the final-ye…
Discovery of an X-ray Luminous Radio-Loud Quasar at : A Possible Transitional Super-Eddington Phase
Sakiko Obuchi, Kohei Ichikawa, Satoshi Yamada +11
We report the multiwavelength properties of eFEDS J084222.9+001000 (hereafter ID830), a quasar at , identified as the most X-ray luminous radio-loud quasar in the eROSITA…
A z ~ 0.4 Galaxy Reflecting the high-redshift Little Red Dots: An Extended Starburst with an Overmassive Black Hole
Xiaoyang Chen, Kohei Ichikawa, Masayuki Akiyama +10
One of the most remarkable discoveries of JWST is a population of compact, red sources at z > 4, commonly referred to as Little Red Dots (LRDs). Spectroscopic identifications repor…
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…
Ongoing and fossil large-scale outflows detected in a high-redshift radio galaxy: [C II] observations of TN J09242201 at
Kianhong Lee, Masayuki Akiyama, Kotaro Kohno +13
We present Atacama Large Millimeter/submillimeter Array observations of the [C II] 158 m line and the underlying continuum emission of TN J09242201, which is one of the most…
J1406+0102: Dust Obscured Galaxy Hiding Super Eddington Accretion System with Bright Radio Emission
Hikaru Fukuchi, Kohei Ichikawa, Masayuki Akiyama +7
Recent high- quasar observations strongly indicate that super-Eddington accretion is a crucial phase to describe the presence of supermassive black holes (SMBHs) with $M_\mathrm…
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…
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…
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…
The Nuclear Region of NGC1365: Star Formation, Negative Feedback, and Outflow Structure
Yulong Gao, Fumi Egusa, Guilin Liu +5
High-resolution observations of ionized and molecular gas in the nuclear regions of galaxies are indispensable for delineating the interplay of star formation, gaseous inflows, ste…
NuSTAR Non-detection of a Faint Active Galactic Nucleus in an Ultraluminous IR Galaxy with Kpc-scale Fast Wind
Xiaoyang Chen, Kohei Ichikawa, Hirofumi Noda +4
Large-scale outflows are generally considered as a possible evidence that active galactic nuclei (AGNs) can severely affect their host galaxies. Recently an ultraluminous IR galaxy…
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…
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…
Simulating the timescale dependent color variation in quasars with a revised inhomogeneous disk model
Zhen-Yi Cai, Jun-Xian Wang, Wei-Min Gu +4
The UV/optical variability of active galactic nuclei and quasars is useful for understanding the physics of the accretion disk and is gradually attributed to the stochastic fluctua…
Analyses on the Variability Asymmetry of Kepler AGNs
Xiao-Yang Chen, Jun-Xian Wang
The high quality light curves of Kepler space telescope make it possible to analyze the optical variability of AGNs with an unprecedented time resolution. Studying the asymmetry in…
The Discovery of Timescale-Dependent Color Variability of Quasars
Yu-Han Sun, Jun-Xian Wang, Xiao-Yang Chen +1
Quasars are variable on timescales from days to years in UV/optical, and generally appear bluer while they brighten. The physics behind the variations in fluxes and colors remains…