Molecular outflow in the reionization-epoch quasar J2054-0005 revealed by OH 119 $\mu$m observations

Dragan Salak; Takuya Hashimoto; Akio K. Inoue; Tom J. L. C. Bakx; Darko Donevski; Yoichi Tamura; Yuma Sugahara; Nario Kuno; Yusuke Miyamoto; Seiji Fujimoto; Suphakorn Suphapolthaworn

arXiv · 2307.02104

Molecular outflow in the reionization-epoch quasar J2054-0005 revealed by OH 119 $\mu$m observations

Dragan Salak·Takuya Hashimoto·Akio K. Inoue·Tom J. L. C. Bakx·Darko Donevski·Yoichi Tamura·Yuma Sugahara·Nario Kuno·Yusuke Miyamoto·Seiji Fujimoto·Suphakorn Suphapolthaworn

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Abstract

Molecular outflows are expected to play a key role in galaxy evolution at high redshift. To study the impact of outflows on star formation at the epoch of reionization, we performed sensitive ALMA observations of OH 119 $\mu$m toward J2054-0005, a luminous quasar at $z=6.04$. The OH line is detected and exhibits a P-Cygni profile that can be fitted with a broad blue-shifted absorption component, providing unambiguous evidence of an outflow, and an emission component at near-systemic velocity. The mean and terminal outflow velocities are estimated to be $v_\mathrm{out}\approx670~\mathrm{km~s}^{-1}$ and $1500~\mathrm{km~s}^{-1}$, respectively, making the molecular outflow in this quasar one of the fastest at the epoch of reionization. The OH line is marginally spatially resolved for the first time in a quasar at $z>6$, revealing that the outflow extends over the central 2 kpc region. The mass outflow rate is comparable to the star formation rate ($\dot{M}_\mathrm{out}/\mathrm{SFR}\sim2$), indicating rapid ($\sim10^7~\mathrm{yr}$) quenching of star formation. The mass outflow rate in a sample star-forming galaxies and quasars at $4<z<6.4$ exhibits a positive correlation with the total infrared luminosity, although the scatter is large. Owing to the high outflow velocity, a large fraction (up to $\sim50\%$) of the outflowing molecular gas may be able to escape from the host galaxy into the intergalactic medium.

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Dragan Salak, Takuya Hashimoto, Akio K. Inoue, Tom J. L. C. Bakx, Darko Donevski, Yoichi Tamura, Yuma Sugahara, Nario Kuno, Yusuke Miyamoto, Seiji Fujimoto, Suphakorn Suphapolthaworn. 2023-07-05. Molecular outflow in the reionization-epoch quasar J2054-0005 revealed by OH 119 $\mu$m observations. https://arxiv.org/abs/2307.02104

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