Year: 2026
Type: preprint
Abstract: We present the discovery and first characterization of $\textit{Nāpōwawā`enakaulua}$: the most compact known quasar pair candidate in the Epoch of Reionization, with a projected separation of only $0.98^{\prime\prime}$ ($\approx 5.56$ pkpc at $z \sim 6.08$) and a velocity offset of $Δv \simeq 15 \text{ km s}^{-1}$. Using spectroscopy from JWST/NIRSpec IFU, as part of the $\textit{Aether survey}$, Gemini/GNIRS and GMOS we characterize the continuum and emission line properties of the two quasars, enabling constraints on their black hole masses ($M_{\text{BH}} \simeq 1.5 \times 10^9$ and $4.0 \times 10^8\,M_\odot$), accretion states ($λ_{\text{Edd}} \simeq 1.23$ and $1.07$), and systemic redshifts ($z_{\rm sys} \simeq 6.0781$ 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 $\sim 2-3$ 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. $\textit{Nāpōwawā`enakaulua}$ thus represents a crucial signpost to investigate the mass assembly of the first massive galaxies and black holes.
Source: arXiv (Cornell University)
Authors: Onorato, Silvia, Farina, Emanuele Paolo, Decarli, Roberto, Protušová, Klaudia, Pizzati, Elia, Pelliccia, Debora, Chu, Devin S., Kimura, Larry Lindsey, Lozi, Leinani, Peavy, Emily, Arrigoni-Battaia, Fabrizio, Bañados, Eduardo, Barth, Aaron J., Belladitta, Silvia, Bischetti, Manuela, Bosman, Sarah E. I., Choi, Hyunseop, Costa, Tiago, Eilers, Anna-Christina, Fan, Xiaohui, Gallerani, Simona, Geballe, Thomas R., Gloudemans, Anniek J., Kim, Eunchong, Lemaux, Brian C., Liu, Weizhe, Matsuoka, Yoshiki, Mazzucchelli, Chiara, Nitta, Atsuko, Schindler, Jan-Torge, Stephens, Andrew W., Suh, Hyewon, Walter, Fabian, Wang, Feige, Yang, Jinyi
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, Space Telescope Science Institute, Deutsche Forschungsgemeinschaft, Korea Astronomy and Space Science Institute, Ministério da Ciência, Tecnologia, Inovações e Comunicações, Agencia Nacional de Investigación y Desarrollo
Awards: G103270039, G256731684, Entstehung und frühe Entwicklung supermassereicher schwarzer Löcher in den ersten zwei Milliarden Jahren unseres Universums, G432818845, A PANCHROMATIC VIEW OF RADIO-LOUD QUASARS IN THE EARLY UNIVERSE, EXC 2121: Quantum Universe, CENTRO DE ASTROFISICA Y TECNOLOGIAS AFINES (CATA)
OpenAlex ID: W7214765603