1. Detection of the [O I] 63 $\mu$m emission line from the $z = 6.04$ quasar J2054-0005
- Author
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Ishii, Nozomi, Hashimoto, Takuya, Ferkinhoff, Carl, Rybak, Matus, Inoue, Akio K., Michiyama, Tomonari, Donevski, Darko, Fujimoto, Seiji, Salak, Dragan, Kuno, Nario, Matsuo, Hiroshi, Mawatari, Ken, Tamura, Yoichi, Izumi, Takuma, Nagao, Tohru, Nakazato, Yurina, Osone, Wataru, Sugahara, Yuma, Usui, Mitsutaka, Wakasugi, Koki, Yajima, Hidenobu, Bakx, Tom J. L. C., Fudamoto, Yoshinobu, Meyer, Romain A., Walter, Fabian, and Yoshida, Naoki
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
We report the highest-redshift detection of [O I] 63 $\mu$m from a luminous quasar, J2054-0005, at $z=6.04$ based on the Atacama Large Millimeter/sub-millimeter Array Band 9 observations. The [O I] 63 $\mu$m line luminosity is $(4.5\pm1.5) \times 10^{9}~L_{\rm \odot}$, corresponding to the [O I] 63 $\mu$m-to-far-infrared luminosity ratio of $\approx 6.7\times10^{-4}$, which is consistent with the value obtained in the local universe. Remarkably, [O I] 63 $\mu$m is as bright as [C II] 158 $\mu$m, resulting in the [O I]-to-[C II] line luminosity ratio of $1.3\pm0.5$. Based on a careful comparison of the luminosity ratios of [O I] 63 $\mu$m, [C II] 158 $\mu$m, and dust continuum emission to models of photo-dissociation regions, we find that J2054-0005 has a gas density log($n_{\rm H}$/cm$^{-3}$)$=3.7\pm0.3$ and an incident far-ultraviolet radiation field of log($G/G_{\rm 0}$)$= 3.0\pm0.1$, showing that [O I] 63 $\mu$m serves as an important coolant of the dense and warm gas in J2054-0005. A close examination of the [O I] and [C II] line profiles suggests that the [O I] line may be partially self-absorbed, however deeper observations are needed to verify this conclusion. Regardless, the gas density and incident radiation field are in a broad agreement with the values obtained in nearby star-forming galaxies and objects with [O I] 63 $\mu$m observations at $z=1-3$ with the Herschel Space Observatory. These results demonstrate the power of ALMA high-frequency observations targeting [O I] 63 $\mu$m to examine the properties of photo-dissociation regions in high-redshift galaxies., Comment: Submitted to PASJ. 5 figures and 3 tables. Comments are very welcome
- Published
- 2024