Probing the full CO spectral line energy distribution (SLED) in the nuclear region of a quasar-starburst system at $z=6.003$

Abstract

We report Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO $(8-7)$, $(9-8)$, ${\mathrm{H}}_2\mathrm{O}(2_{0,2}-1_{1,1})$ and $\mathrm{O}{\mathrm{H}}^{+}(1_1-0_1)$ and NOrthern Extended Millimeter Array (NOEMA) observations of CO $(5-4)$, $(6-5)$, $(12-11)$ and $(13-12)$ towards the $z=6.003$ quasar SDSS J231038.88+185519.7, aiming to probe the physical conditions of the molecular gas content of this source. We present the best sampled CO spectral line energy distribution (SLED) at $z=6.003$, and analyzed it with the radiative transfer code MOLPOP-CEP. Fitting the CO SLED to a one-component model indicates a kinetic temperature $T_{\mathrm{kin}}=228\mathrm{K}$, molecular gas density $log(n({\mathrm{H}}_2)/\mathrm{c}{\mathrm{m}}^{-3}$ )=4.75, and CO column density $log(N(\mathrm{CO})/\mathrm{c}{\mathrm{m}}^{-2})=17.5$, although a two-component model better fits the data. In either case, the CO SLED is dominated by a "warm" and "dense" component. Compared to samples of local (Ultra) Luminous Infrared Galaxies ((U)LIRGs), starburst galaxies and high redshift Submillimeter Galaxies (SMGs), J2310+1855 exhibits higher CO excitation at ($J\ge 8$), like other high redshift quasars. The high CO excitation, together with the enhanced $L_{{\mathrm{H}}_2\mathrm{O}}/L_{IR}$, $L_{{\mathrm{H}}_2\mathrm{O}}/L_{CO}$ and $L_{O{H}^{+}}/L_{{\mathrm{H}}_2\mathrm{O}}$ ratios, suggests that besides the UV radiation from young massive stars, other mechanisms such as shocks, cosmic rays and X-rays might also be responsible for the heating and ionization of the molecular gas. In the nuclear region probed by the molecular emissions lines, any of these mechanisms might be present due to the powerful quasar and the starburst activity.

21 pages, 7 figures, accepted for publication in Apj

References in corpus (28)

• A Dust-Obscured Massive Maximum-Starburst Galaxy at a Redshift of 6.34
• Diagnostics of irradiated dense gas in galaxy nuclei. II. A grid of XDR and PDR models
• 350 Micron Dust Emission from High Redshift Quasars
• The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
• CO excitation of normal star forming galaxies out to z=1.5 as regulated by the properties of their interstellar medium
• A Kiloparsec-Scale Hyper-Starburst in a Quasar Host Less than 1 Gigayear after the Big Bang
• Gemini Near-infrared Spectroscopy of Luminous z~6 Quasars: Chemical Abundances, Black Hole Masses, and MgII Absorption
• Highly-excited CO emission in APM08279+5255 at z=3.9
• The Herschel Comprehensive (U)LIRG Emission Survey (HerCULES): CO Ladders, fine structure lines, and neutral gas cooling
• Star formation relations and CO SLEDs across the J-ladder and redshift
• CO(1-0) in z >/~ 4 Quasar Host Galaxies: No Evidence for Extended Molecular Gas Reservoirs
• Molecular line emission in NGC1068 imaged with ALMA: II. The chemistry of the dense molecular gas
• Thermal Emission from Warm Dust in the Most Distant Quasars
• ALMA observations of atomic carbon in z~4 dusty star-forming galaxies
• Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z~2-4 as probed by multi-J CO lines
• Copious Amounts of Dust and Gas in a z=7.5 Quasar Host Galaxy
• Imaging the Molecular Gas in a z=3.9 Quasar Host Galaxy at 0.3" Resolution: A Central, Sub-Kiloparsec Scale Star Formation Reservoir in APM 08279+5255
• Large turbulent reservoirs of cold molecular gas around high-redshift starburst galaxies
• Molecular gas in three z~7 quasar host galaxies
• 400 pc Imaging of a Massive Quasar Host Galaxy at a Redshift of 6.6
• Spatially Resolved Interstellar Medium and Highly-Excited Dense Molecular Gas in the Most Luminous Quasar at z=6.327
• First CO(17-16) emission line detected in a z > 6 quasar
• Submillimeter H2O and H2O+ emission in lensed ultra- and hyper-luminous infrared galaxies at z ~ 2-4
• Bright [CII] 158$\mu$m emission in a quasar host galaxy at $z=6.54$
• Gas dynamics of a luminous $z$ = 6.13 quasar ULAS J1319$+$0950 revealed by ALMA high resolution observations
• Modeling the H2O submillimeter emission in extragalactic sources
• Star Formation and ISM Properties in Host Galaxies of Three Far-infrared Luminous Quasars at $z\sim 6$
• Constraining the ISM properties of the Cloverleaf quasar host galaxy with Herschel spectroscopy

Cited by in corpus (30)

• Photodissociation and X-Ray Dominated Regions
• The WISSH QSOs project IX. Cold gas content and environment of luminous QSOs at z~2.4-4.7
• An ALMA multi-line survey of the ISM in two quasar host-companion galaxy pairs at $z>6$
• Host galaxies of high-redshift quasars: supermassive black hole growth and feedback
• An empirical study of dust properties at the earliest epochs
• Molecular gas in z~6 quasar host galaxies
• Infrared emission of $z\sim 6$ galaxies: AGN imprints
• Molecular Line Observations in Two Dusty Star-Forming Galaxies at z = 6.9
• Close-up view of a luminous star-forming galaxy at z=2.95
• The interstellar medium distribution, gas kinematics, and system dynamics of the far-infrared luminous quasar SDSS J2310+1855 at $z=6.0$
• PDFchem: A new fast method to determine ISM properties and infer environmental parameters using probability distributions
• A comprehensive view of the interstellar medium in a quasar host galaxy at z~6.4
• Red quasars blow out molecular gas from galaxies during the peak of cosmic star formation
• A quasar-galaxy merger at $z\sim 6.2$: rapid host growth via accretion of two massive satellite galaxies
• The GADOT Galaxy Survey: Dense Gas and Feedback in Herschel-Selected Starburst Galaxies at Redshifts 2 to 6
• The black hole and host galaxy growth in an isolated $z\sim 6$ QSO observed with ALMA
• HYPERION. Coevolution of supermassive black holes and galaxies at $z>6$ and the build-up of massive galaxies
• Molecular Outflows in z > 6 QSO Hosts Driven by Star Formation
• Spatially resolved molecular interstellar medium in a $z=6.6$ quasar host galaxy
• Big Three Dragons: Molecular Gas in a Bright Lyman-Break Galaxy at $z=7.15$
• Unveiling the warm dense ISM in $z>6$ quasar host galaxies via water vapor emission
• Detection of H2O and OH+ in z>3 Hot Dust-Obscured Galaxies
• Constraints on the electron-to-proton mass ratio variation at the epoch of reionization
• Dense and warm neutral gas in BR1202-0725 at z = 4.7 as traced by the [O I] 145 um line
• Dynamical signature of a stellar bulge in a quasar host galaxy at $z\simeq 6$
• Simulated [CII] in high-z galaxies
• Central concentration of warm and dense molecular gas in a strongly lensed submillimeter galaxy at z=6
• Warm Gas in the Vicinity of a Supermassive Black hole 13 Billion Years Ago
• Neutral outflows in high-z QSOs
• Unveiling the evolution of the CO excitation ladder through cross-correlation of CONCERTO-like experiments and galaxy redshift surveys