Masatoshi Imanishi

SHELLQs. Black Hole Mass and Eddington Ratio Distributions of Intermediate-Luminosity Quasars at 6<z<7

Masafusa Onoue, John D. Silverman, Yoshiki Matsuoka +31

We present near-infrared spectroscopy of 21 quasars at 6.07 < z < 6.90 obtained with JWST/NIRSpec and Subaru/MOIRCS. These targets have absolute ultraviolet magnitudes of -25 < M_1…

SERENADE III: Insight into the Origin of the High Dust Temperature and High [O III]/[C II] Ratio at $z ≳ 6$

Ikki Mitsuhashi, Yuichi Harikane, Hiddo S. B. Algera +10

We present an analysis of ALMA high-frequency observations of nine bright Lyman-break galaxies at $5.8 < z_{spec} < 8.3$ . Our sample consists of five galaxies at $z \sim 6$ newly obs…

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…

Subaru High- $z$ Exploration of Low-Luminosity Quasars (SHELLQs). XXV. Large-scale environments of low-luminosity quasars at $z \sim 6$ traced by Ly $α$ emitters

Junya Arita, Nobunari Kashikawa, Yoshiki Matsuoka +18

High- $z$ quasars are believed to reside in massive dark matter haloes (DMHs), suggesting that they reside in galaxy overdense regions. However, previous observations have shown a r…

MAJORS II: HCO+& HCN Abundances in W40

René Plume, David J. Eden, Malcolm J. Currie +34

We present observations of HCN and HCO $^{+}$ J = $3 - 2$ in the central $42 4^{''} \times 42 4^{''}$ region of the W40 massive star forming region. The observations were taken as part of a p…

HST Confirms Sub-5 kpc Dual Quasar Pairs at Cosmic Noon

Qian Wang, Xuheng Ding, John Silverman +12

During cosmic noon ( $z \sim 1 - 3$ ), when both star formation and black hole growth peaked, galaxy mergers are predicted to trigger dual active galactic nuclei (AGN) that eventually co…

ALMA Sub-parsec Resolution Dense Molecular Line Observations of the NGC 1068 Nucleus

Masatoshi Imanishi, Bernd Vollmer, Yoshiaki Hagiwara +3

We present the results of our ALMA observations of the dense molecular HCN J=4-3 and HCO $^{+}$ J=4-3 lines at $≲$ 1 pc ( $≲$ 14 mas) resolution in the nuclear region of…

astro-ph.GA2025★ 1 cited

SHELLQs-JWST: Revealing the Spectra of Extended Emission in 12 z > 6 Quasar Host Galaxies using the JWST NIRSpec Fixed Slit

Camryn L. Phillips, Michael A. Strauss, Masafusa Onoue +15

We present an analysis of the rest frame optical JWST NIRSpec Fixed Slit spectra of extended host galaxy emission in 12 quasars from the Subaru High-z Exploration of Low-Luminosity…

Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). XXIV. 54 New Quasars and Candidate Obscured Quasars at $5.71 \leq z \leq 7.02$

Yoshiki Matsuoka, Kazushi Iwasawa, Masafusa Onoue +18

We present spectroscopic identification of 43 quasars and 11 candidate obscured quasars in the epoch of reionization (EoR) at $5.71 \leq z \leq 7.02$ , along with 29 galaxies at simil…

Merger fraction in galaxy groups and clusters at z < 0.2: A non-parametric morphological study with Subaru Hyper Suprime-Cam

Anri Yanagawa, Yoshiki Toba, Naomi Ota +7

We investigate the environmental dependence of galaxy mergers using high-resolution imaging data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program. We focus on galaxy group…

SHELLQs-JWST perspective on the intrinsic mass relation between supermassive black holes and their host galaxies at z > 6

John Silverman, Junyao Li, Xuheng Ding +36

The relation between the masses of supermassive black holes (SMBHs) and their host galaxies encodes information on their mode of growth, especially at the earliest epochs. The Jame…

astro-ph.GA2025★ 4 cited

UNIONS Optical Identifications for VLASS Radio Sources in the Euclid Sky (UNVEIL) I. A Catalog of ~146,000 Radio Galaxies up to z~5

Yuxing Zhong, Kohei Ichikawa, Hendrik Hildebrandt +11

We present results of optical identifications for Very Large Array Sky Survey (VLASS) radio sources using the Ultraviolet Near Infrared Optical Northern Survey (UNIONS). A cross-ma…

astro-ph.GA2025★ 13 cited

Quasar Negative Feedback to Surrounding Galaxies Probed with Ly $α$ Emitters and Continuum-Selected Galaxies

Yuta Suzuki, Yoshiki Matsuoka, Satoshi Kikuta +3

We report on the statistical analysis of quasar photoevaporation at $z \sim 2.2$ by comparing the density of surrounding Ly $α$ Emitters (LAEs) and continuum-selected galaxies, based…

SHELLQs. Bridging the Gap: JWST Unveils Obscured Quasars in the Most Luminous Galaxies at z > 6

Yoshiki Matsuoka, Masafusa Onoue, Kazushi Iwasawa +17

The unprecedented sensitivity of the James Webb Space Telescope (JWST) has uncovered a surprisingly abundant population of mildly obscured, low-luminosity active galactic nuclei (A…

astro-ph.GA2025★ 10 cited

SHELLQs-JWST Unveils the Host Galaxies of 12 Quasars at z>6

Xuheng Ding, Masafusa Onoue, John D. Silverman +35

The advent of JWST has opened new horizons in the study of quasar host galaxies during the reionization epoch (z>6). Building upon our previous initial measurements of stellar ligh…

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…

astro-ph.GA2024★ 2 cited

A Post-Starburst Pathway for the Formation of Massive Galaxies and Black Holes at z>6

Masafusa Onoue, Xuheng Ding, John D. Silverman +45

Understanding the rapid formation of supermassive black holes (SMBHs) in the early universe requires insight into stellar mass growth in host galaxies. Here, we present NIRSpec res…

Discovery of a hyperluminous quasar at z = 1.62 with Eddington ratio > 3 in the eFEDS field confirmed by KOOLS-IFU on Seimei Telescope

Yoshiki Toba, Keito Masu, Naomi Ota +17

We report the discovery of a hyperluminous type 1 quasar (eFEDS J082826.9-013911; eFEDSJ0828-0139) at $z_{spec}$ = 1.622 with a super-Eddington ratio ( $λ_{Edd}$ ). We perfor…

astro-ph.GA2024★ 4 cited

Environments around quasars at $z \sim$ 3 revealed by wide-field imaging with Subaru HSC and CFHT

Yuta Suzuki, Hisakazu Uchiyama, Yoshiki Matsuoka +7

We examine the local density environments around 67 quasars at $z \sim 3$ , by combining the imaging data of Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) and Canada-France-Haw…

Rich and diverse molecular gas environments of closely-separated dual quasars viewed by ALMA

Shenli Tang, John D. Silverman, Zhaoxuan Liu +12

We present a study of the molecular gas in five closely-spaced ( $R_{⊥} < 20$ kpc) dual quasars ( $L_{bol} ≳ 1 0^{44} erg s^{- 1}$ ) at redshifts $0.4 < z < 0.8$ with the…

Ongoing and fossil large-scale outflows detected in a high-redshift radio galaxy: [C II] observations of TN J0924 $-$ 2201 at $z = 5.174$

Kianhong Lee, Masayuki Akiyama, Kotaro Kohno +13

We present Atacama Large Millimeter/submillimeter Array observations of the [C II] 158 $μ$ m line and the underlying continuum emission of TN J0924 $-$ 2201, which is one of the most…