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

@misc{onoue2026shellqs,
  title = {{SHELLQs. Black Hole Mass and Eddington Ratio Distributions of Intermediate-Luminosity Quasars at 6<z<7}},
  author = {Masafusa Onoue and John D. Silverman and Yoshiki Matsuoka and Xuheng Ding and Camryn L. Phillips and Michael A. Strauss and Junya Arita and Takuma Izumi and Mahoshi Sawamura and Nobunari Kashikawa and Irham Andika and Kentaro Aoki and Shunsuke Baba and Anna-Christina Eilers and Seiji Fujimoto and Tomotsugu Goto and Masatoshi Imanishi and Kohei Inayoshi and Kazushi Iwasawa and Knud Jahnke and Yuki Kaneko and Toshihiro Kawaguchi and Kotaro Kohno and Chien-Hsiu Lee and Alessandro Lupi and Tohru Nagao and Dragan Salak and Malte Schramm and Yoshiki Toba and Hideki Umehata and Marta Volonteri and Fabian Walter and Feige Wang and Jinyi Yang},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.09266},
  eprint = {2609.09266},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.09266},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - SHELLQs. Black Hole Mass and Eddington Ratio Distributions of Intermediate-Luminosity Quasars at 6<z<7
AU  - Masafusa Onoue
AU  - John D. Silverman
AU  - Yoshiki Matsuoka
AU  - Xuheng Ding
AU  - Camryn L. Phillips
AU  - Michael A. Strauss
AU  - Junya Arita
AU  - Takuma Izumi
AU  - Mahoshi Sawamura
AU  - Nobunari Kashikawa
AU  - Irham Andika
AU  - Kentaro Aoki
AU  - Shunsuke Baba
AU  - Anna-Christina Eilers
AU  - Seiji Fujimoto
AU  - Tomotsugu Goto
AU  - Masatoshi Imanishi
AU  - Kohei Inayoshi
AU  - Kazushi Iwasawa
AU  - Knud Jahnke
AU  - Yuki Kaneko
AU  - Toshihiro Kawaguchi
AU  - Kotaro Kohno
AU  - Chien-Hsiu Lee
AU  - Alessandro Lupi
AU  - Tohru Nagao
AU  - Dragan Salak
AU  - Malte Schramm
AU  - Yoshiki Toba
AU  - Hideki Umehata
AU  - Marta Volonteri
AU  - Fabian Walter
AU  - Feige Wang
AU  - Jinyi Yang
PY  - 2026
DA  - 2026/09/08
PB  - arXiv
DO  - 10.48550/arxiv.2609.09266
UR  - https://arxiv.org/abs/2609.09266
AB  - 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_1450 < -22 and are drawn from a sample of z>6 quasars identified in the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project. These quasars occupy the intermediate-luminosity regime between luminous quasars and the faint high-redshift AGNs uncovered by JWST. We detect broad Balmer emission lines and MgII 2798 with underlying continua from the NIRSpec and MOIRCS targets, respectively. The virial black hole masses of this sample span a wide range of 7.2 < log M_BH/M_sun < 9.4, with Eddington ratios of -1.3 < log L_bol/L_Edd < 0.4. Combining these measurements with our previous mass estimates for other SHELLQs quasars, we construct a sample of 27 quasars with M_BH estimates at 6 < z < 7 and derive the distributions of M_BH and L_bol/L_Edd. When compared with luminosity-matched quasars at z ~ 1.3, we find median offsets of delta log M_BH/M_sun = -0.4 and Delta log L_bol/L_Edd = 0.2 in the high-redshift sample. In addition, 11% of the high-redshift quasars are accreting near or above the Eddington limit. As a systematic check, adopting the Eddington-ratio-dependent calibration of single-epoch M_BH estimates increases the inferred super-Eddington fraction to 22%. These results indicate that a representative population of distant supermassive black holes undergo a rapid accretion phase, although not as extreme as that seen in the most luminous quasar population, consistent with the anti-hierarchical growth scenario of supermassive black holes.
ER  -