학술논문
First rest-frame infrared spectrum of a z>7 quasar: JWST/MRS observations of J1120+0641
Document Type
Working Paper
Author
Bosman, Sarah E. I.; Álvarez-Márquez, Javier; Colina, Luis; Walter, Fabian; Alonso-Herrero, Almudena; Ward, Martin J.; Östlin, Göran; Greve, Thomas R.; Wright, Gillian; Bik, Arjan; Boogaard, Leindert; Caputi, Karina I.; Costantin, Luca; Eckart, Andreas; García-Marín, Macarena; Gillman, Steven; Güdel, Manuel; Henning, Thomas; Hjorth, Jens; Iani, Edoardo; Ilbert, Olivier; Jermann, Iris; Labiano, Alvaro; Lagage, Pierre-Olivier; Langeroodi, Danial; Peißker, Florian; Ray, Tom P.; Rinaldi, Pierluigi; Topinka, Martin; van Dishoeck, Ewine F.; van der Werf, Paul; Vandenbussche, Bart
Source
Subject
Language
Abstract
We present a JWST/MRS spectrum of the quasar J1120+0641 at z=7.0848, the first spectroscopic observation of a reionisation-era quasar in the rest-frame infrared ($0.6<\lambda<3.4\mu$m). In the context of the mysterious fast assembly of the first supermassive black holes at z>7, our observations enable for the first time the detection of hot torus dust, the H$\alpha$ emission line, and the Paschen-series broad emission lines in a quasar at z>7. Hot torus dust is clearly detected as an upturn in the continuum emission at $\lambda_{\text{rest}}\simeq1.3\mu$m, leading to a black-body temperature of $T=1413.5^{+5.7}_{-7.4}$K. Compared to similarly-luminous quasars at 06 ($2\sigma$ significance). We measure the black hole mass of J1120+0641 based on the H$\alpha$ Balmer line, $M_{\text{BH}}=1.52\pm0.17\cdot 10^9 M_\odot$, which is in good agreement with the previous rest-UV MgII black hole mass measurement. The black hole mass based on the Paschen-series lines is also consistent, indicating no significant extinction in the rest-frame UV measurement. The broad H$\alpha$, Pa-$\alpha$ and Pa-$\beta$ emission lines are consistent with an origin in a common broad-line region (BLR) with density log$N_H/\text{cm}^{-3}\geq 12$, ionisation parameter $-7<$log$U<-4$, and extinction E(B-V)$\lesssim 0.1$mag. These BLR parameters are consistent with similarly-bright quasars at 0 Comment: 19 pages, 10 figures; submitted