7 papers
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…
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-Redshift Radio Quasar candidates beyond Ultra-Steep Spectrum Selection: Dropout selection from HSC--VLASS over 1200 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-Cam Su…
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…
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…
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…