The interstellar medium distribution, gas kinematics, and system dynamics of the far-infrared luminous quasar SDSS J2310+1855 at z = 6.0 - Archive ouverte HAL Access content directly
Journal Articles Astronomy & Astrophysics Year : 2022

The interstellar medium distribution, gas kinematics, and system dynamics of the far-infrared luminous quasar SDSS J2310+1855 at z = 6.0

Yali Shao
  • Function : Author
Ran Wang
  • Function : Author
Axel Weiss
  • Function : Author
Jeff Wagg
  • Function : Author
Chris L. Carilli
  • Function : Author
Michael A. Strauss
  • Function : Author
Fabian Walter
  • Function : Author
Xiaohui Fan
  • Function : Author
Karl M. Menten
  • Function : Author
Desika Narayanan
  • Function : Author
Dominik Riechers
  • Function : Author
Frank Bertoldi
  • Function : Author
Linhua Jiang
  • Function : Author


We present Atacama Large Millimeter/submillimeter Array (ALMA) sub-kiloparsec- to kiloparsec-scale resolution observations of the [C II], CO (9-8), and OH+ (11-01) lines along with their dust continuum emission toward the far-infrared (FIR) luminous quasar SDSS J231038.88+185519.7 at z = 6.0031, to study the interstellar medium distribution, the gas kinematics, and the quasar-host system dynamics. We decompose the intensity maps of the [C II] and CO (9-8) lines and the dust continuum with two-dimensional elliptical Sérsic models. The [C II] brightness follows a flat distribution with a Sérsic index of 0.59. The CO (9-8) line and the dust continuum can be fit with an unresolved nuclear component and an extended Sérsic component with a Sérsic index of ∼1, which may correspond to the emission from an active galactic nucleus dusty molecular torus and a quasar host galaxy, respectively. The different [C II] spatial distribution may be due to the effect of the high dust opacity, which increases the FIR background radiation on the [C II] line, especially in the galaxy center, significantly suppressing the [C II] emission profile. The dust temperature drops with distance from the center. The effective radius of the dust continuum is smaller than that of the line emission and the dust mass surface density, but is consistent with that of the star formation rate surface density. This may indicate that the dust emission is a less robust tracer of the dust and gas distribution but is a decent tracer of the obscured star formation activity. The OH+ (11-01) line shows a P-Cygni profile with an absorption at ∼-400 km s−1, which may indicate an outflow with a neutral gas mass of (6.2 ± 1.2)×108 M along the line of sight. We employed a three-dimensional tilted ring model to fit the [C II] and CO (9-8) data cubes. The two lines are both rotation dominated and trace identical disk geometries and gas motions. This suggest that the [C II] and CO (9-8) gas are coplanar and corotating in this quasar host galaxy. The consistent circular velocities measured with [C II] and CO (9-8) lines indicate that these two lines trace a similar gravitational potential. We decompose the circular rotation curve measured from the kinematic model fit to the [C II] line into four matter components (black hole, stars, gas, and dark matter). The quasar-starburst system is dominated by baryonic matter inside the central few kiloparsecs. We constrain the black hole mass to be 2.97+0.51-0.77 × 109 M; this is the first time that the dynamical mass of a black hole has been measured at z ∼ 6. This mass is consistent with that determined using the scaling relations from quasar emission lines. A massive stellar component (on the order of 109 M) may have already existed when the Universe was only ∼0.93 Gyr old. The relations between the black hole mass and the baryonic mass of this quasar indicate that the central supermassive black hole may have formed before its host galaxy.
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hal-03974054 , version 1 (07-02-2023)


Attribution - CC BY 4.0



Yali Shao, Ran Wang, Axel Weiss, Jeff Wagg, Chris L. Carilli, et al.. The interstellar medium distribution, gas kinematics, and system dynamics of the far-infrared luminous quasar SDSS J2310+1855 at z = 6.0. Astronomy & Astrophysics, 2022, 668, ⟨10.1051/0004-6361/202244610⟩. ⟨hal-03974054⟩
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