TY - JOUR
T1 - The interstellar medium distribution, gas kinematics, and system dynamics of the far-infrared luminous quasar SDSS J2310+1855 at z = 6.0
AU - Shao, Yali
AU - Wang, Ran
AU - Weiss, Axel
AU - Wagg, Jeff
AU - Carilli, Chris L.
AU - Strauss, Michael A.
AU - Walter, Fabian
AU - Cox, Pierre
AU - Fan, Xiaohui
AU - Menten, Karl M.
AU - Narayanan, Desika
AU - Riechers, Dominik
AU - Bertoldi, Frank
AU - Omont, Alain
AU - Jiang, Linhua
N1 - Funding Information:
We would like to dedicate this paper to the memory of Dr. Yu Gao. Dr. Gao passed away on 21 May 2022. During his career, Dr. Gao made numerous key contributions to the physics of star formation and the interstellar medium in galaxies; in particular, his work established the star formation law in terms of dense molecular gas content. Dr. Gao left a lasting legacy as a brilliant scientist, as a most respected colleague and caring mentor, and above all, a true gentleman. Dr. Gao will always be in our hearts and thoughts as a truly remarkable human being. We would like to thank the anonymous reviewer for all valuable comments and suggestions, which helped us to improve the quality of the manuscript. This work makes use of the following ALMA data: ADS/JAO.ALMA# 2018.1.00597.S; 2015.1.01265.S; 2015.1.00997.S and 2011.0.00206.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. R.W. acknowledges supports from the National Science Foundation of China (NSFC) grants No. 12173002, 11991052, 11721303, and 11533001, and the science research grants from the China Manned Space Project with No. CMS-CSST-2021-A06. Y.S. acknowledges discussions with Francesca Rizzo, Gang Wu, Aiyuan Yang and Sudeep Neupane.
Publisher Copyright:
© 2022 EDP Sciences. All rights reserved.
PY - 2022/12/1
Y1 - 2022/12/1
N2 - We present Atacama Large Millimeter/submillimeter Array (ALMA) sub-kiloparsec- to kiloparsec-scale resolution observations of the [Ca 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 [Ca II] and CO (9-8) lines and the dust continuum with two-dimensional elliptical Sérsic models. The [Ca 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 [Ca II] spatial distribution may be due to the effect of the high dust opacity, which increases the FIR background radiation on the [Ca II] line, especially in the galaxy center, significantly suppressing the [Ca 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 [Ca 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 [Ca II] and CO (9-8) gas are coplanar and corotating in this quasar host galaxy. The consistent circular velocities measured with [Ca 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 [Ca 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.
AB - We present Atacama Large Millimeter/submillimeter Array (ALMA) sub-kiloparsec- to kiloparsec-scale resolution observations of the [Ca 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 [Ca II] and CO (9-8) lines and the dust continuum with two-dimensional elliptical Sérsic models. The [Ca 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 [Ca II] spatial distribution may be due to the effect of the high dust opacity, which increases the FIR background radiation on the [Ca II] line, especially in the galaxy center, significantly suppressing the [Ca 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 [Ca 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 [Ca II] and CO (9-8) gas are coplanar and corotating in this quasar host galaxy. The consistent circular velocities measured with [Ca 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 [Ca 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.
KW - Galaxies: high-redshift
KW - Quasars: general
KW - Submillimeter: galaxies
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U2 - 10.1051/0004-6361/202244610
DO - 10.1051/0004-6361/202244610
M3 - Article
AN - SCOPUS:85145442164
SN - 0004-6361
VL - 668
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A121
ER -