Nāpōwawā`enakaulua: a close quasar pair at cosmic dawn in the Aether survey
Abstract
We present the discovery and first characterization of Nāpōwawā`enakaulua: the most compact known quasar pair candidate in the Epoch of Reionization, with a projected separation of only 0.98′′ (≈ 5.56 pkpc at z ∼ 6.08) and a velocity offset of Δv ≃ 15 km s−1. Using spectroscopy from JWST/NIRSpec IFU, as part of the Aether survey, Gemini/GNIRS and GMOS we characterize the continuum and emission line properties of the two quasars, enabling constraints on their black hole masses (MBH ≃ 1.5 × 109 and 4.0 × 108 M⊙), accretion states (λEdd ≃ 1.23 and $1.07$), and systemic redshifts (zsys ≃ 6.0781 and $6.0785$). We place this pair in the cosmological context by comparing the chance of occurrence to extrapolations of high-z quasar clustering measurements at larger scales, resulting in a ∼ 2−3 order of magnitude excess with respect to expectations. This excess hints at an underlying population of merger-triggered quasar pairs at cosmic dawn or to a denser-than-average galactic environment. Nāpōwawā`enakaulua thus represents a crucial signpost to investigate the mass assembly of the first massive galaxies and black holes.
Related
- Extreme Enrichment at Cosmic Dawn: Three FeII-Strong Quasars at z > 6 from the JWST Aether survey
- Extreme Enrichment at Cosmic Dawn: Three Fe II -strong Quasars at z > 6 from the JWST Aether Survey
- A relativistic inflow candidate in a quasar at cosmic noon
- JWST lensed quasar dark matter survey. IV. Stringent warm dark matter constraints from the joint reconstruction of extended lensed arcs and quasar flux ratios
- The Quasar Feedback Survey: Ionised outflows in type 2 QSOs with MUSE data
BibTeX
@misc{onorato2026nāpōwawāenakaulua,
title = {{$\textitNāpōwawā`enakaulua$: a close quasar pair at cosmic dawn in the Aether survey}},
author = {Silvia Onorato and Emanuele Paolo Farina and Roberto Decarli and Klaudia Protušová and Elia Pizzati and Debora Pelliccia and Devin S. Chu and Larry Lindsey Kimura and Leinani Lozi and Emily Peavy and Fabrizio Arrigoni-Battaia and Eduardo Bañados and Aaron J. Barth and Silvia Belladitta and Manuela Bischetti and Sarah E. I. Bosman and Hyunseop Choi and Tiago Costa and Anna-Christina Eilers and Xiaohui Fan and Simona Gallerani and Thomas R. Geballe and Anniek J. Gloudemans and Eunchong Kim and Brian C. Lemaux and Weizhe Liu and Yoshiki Matsuoka and Chiara Mazzucchelli and Atsuko Nitta and Jan-Torge Schindler and Andrew W. Stephens and Hyewon Suh and Fabian Walter and Feige Wang and Jinyi Yang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.31835},
eprint = {2609.31835},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.31835},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Nāpōwawā`enakaulua: a close quasar pair at cosmic dawn in the Aether survey
AU - Silvia Onorato
AU - Emanuele Paolo Farina
AU - Roberto Decarli
AU - Klaudia Protušová
AU - Elia Pizzati
AU - Debora Pelliccia
AU - Devin S. Chu
AU - Larry Lindsey Kimura
AU - Leinani Lozi
AU - Emily Peavy
AU - Fabrizio Arrigoni-Battaia
AU - Eduardo Bañados
AU - Aaron J. Barth
AU - Silvia Belladitta
AU - Manuela Bischetti
AU - Sarah E. I. Bosman
AU - Hyunseop Choi
AU - Tiago Costa
AU - Anna-Christina Eilers
AU - Xiaohui Fan
AU - Simona Gallerani
AU - Thomas R. Geballe
AU - Anniek J. Gloudemans
AU - Eunchong Kim
AU - Brian C. Lemaux
AU - Weizhe Liu
AU - Yoshiki Matsuoka
AU - Chiara Mazzucchelli
AU - Atsuko Nitta
AU - Jan-Torge Schindler
AU - Andrew W. Stephens
AU - Hyewon Suh
AU - Fabian Walter
AU - Feige Wang
AU - Jinyi Yang
PY - 2026
DA - 2026/09/25
PB - arXiv
DO - 10.48550/arxiv.2609.31835
UR - https://arxiv.org/abs/2609.31835
AB - We present the discovery and first characterization of Nāpōwawā`enakaulua: the most compact known quasar pair candidate in the Epoch of Reionization, with a projected separation of only 0.98^′′ (≈ 5.56 pkpc at z ∼ 6.08) and a velocity offset of Δv ≃ 15 km s^−1. Using spectroscopy from JWST/NIRSpec IFU, as part of the Aether survey, Gemini/GNIRS and GMOS we characterize the continuum and emission line properties of the two quasars, enabling constraints on their black hole masses (M_BH ≃ 1.5 × 10^9 and 4.0 × 10^8 M_⊙), accretion states (λ_Edd ≃ 1.23 and $1.07$), and systemic redshifts (z_sys ≃ 6.0781 and $6.0785$). We place this pair in the cosmological context by comparing the chance of occurrence to extrapolations of high-z quasar clustering measurements at larger scales, resulting in a ∼ 2−3 order of magnitude excess with respect to expectations. This excess hints at an underlying population of merger-triggered quasar pairs at cosmic dawn or to a denser-than-average galactic environment. Nāpōwawā`enakaulua thus represents a crucial signpost to investigate the mass assembly of the first massive galaxies and black holes.
ER -