Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). XIII. Large-scale Feedback and Star Formation in a Low-Luminosity Quasar at z = 7.07 on the Local Black Hole to Host Mass Relation

We present ALMA [CII] 158 $\mu$m line and underlying far-infrared (FIR) continuum emission observations ($0^{\mathrm{\prime }\mathrm{\prime }}.70\times 0^{\mathrm{\prime }\mathrm{\prime }}.56$ resolution) toward HSC J124353.93$+$010038.5 (J1243$+$0100) at $z=7.07$, the only low-luminosity ($M_{1450}>-25$ mag) quasar currently known at $z>7$. The FIR continuum is bright (1.52 mJy) and resolved with a total luminosity of $L_{\rm FIR} = 3.5 \times 10^{12}~L_\odot$\mathrm{.}Thespatiallyextendedcomponentisresponsiblefor$\sim 40%$ of the emission. The area-integrated [CII] spectrum shows a broad wing ($\mathrm{F}\mathrm{W}\mathrm{H}\mathrm{M}=997$ km s${}^{-1}$, $L_{\rm [CII]} = 1.2 \times 10^9~L_\odot$)aswellasabrightcore(${\rm FWHM} = 235$kms$^{-1}$,$L_{\rm [CII]} = 1.9 \times 10^9~L_\odot$). This wing is the first detection of a galactic-scale quasar-driven outflow (atomic outflow rate $>447M_{\odot }$ yr${}^{-1}$) at $z>7$. The estimated large mass loading factor of the total outflow (e.g., $\gtrsim 9$ relative to the [CII]-based SFR) suggests that this outflow will soon quench the star-formation of the host. The core gas dynamics are governed by rotation, with a rotation curve suggestive of a compact bulge ($\sim 3.3\times {10}^{10}{M}_{\odot }$), although it is not yet spatially resolved. Finally, we found that J1243$+$0100 has a black hole mass-to-dynamical mass ratio (and -to-bulge mass ratio) of $\sim 0.4\mathrm{\%}$ ($\sim 1\mathrm{\%}$), consistent with the local value within uncertainties. Our results therefore suggest that the black hole-host co-evolution relation is already in place at $z\sim 7$ for this object.