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

Abstract

We present Atacama Large Millimeter/submillimeter Array [C II]158 μm line and underlying far-infrared (FIR) continuum emission observations (0 70 ×0 56 resolution)toward HSC J124353.93+010038.5 (J1243+0100)at z =7.07, the only low-luminosity (M1450 >−25 mag)quasar currently known at z >7. The FIR continuum is bright (1.52 mJy)and resolved with a total luminosity of LFIR =3.5 ×1012 Le. The spatially extended component is responsible for ∼40% of the emission. The area-integrated [C II]spectrum shows a broad wing (FWHM =997 km s−1, L[C II]=1.2 ×109 Le), as well as a bright core (FWHM =235 km s−1, L[C II]=1.9 ×109 Le). This wing is the first detection of a galactic-scale quasar-driven outflow (atomic outflow rate >447 Meyr−1)at z >7. The estimated large mass-loading factor of the total outflow (e.g., 9 relative to the [C II]-based star formation rate)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 (∼3.3 ×1010 Me), although it is not yet spatially resolved. Finally, we found that J1243+0100 has a black hole mass–to–dynamical mass (and –to–bulge mass)ratio of ∼0.4% (∼1%), consistent with the local value within the uncertainties. Our results therefore suggest that the black hole–host coevolution relation is already in place at z ∼7 for this object.