The CI lines as tracers of molecular gas, and their prospects at high redshifts

Abstract

We examine the fine structure lines ${}^3{P}_1\to$${}^3{P}_0$ (492 GHz) and ${}^3{P}_2\to$${}^3{P}_1$ (809 GHz) of neutral atomic carbon as bulk molecular gas mass tracers and find that they can be good and on many occasions better than ${}^{12}$CO transitions, especially at high redshifts. The notion of CI emission as an H${}_2$ gas mass tracer challenges the long-held view of its distribution over only a relatively narrow layer in the CII/CI/CO transition zone in FUV-illuminated molecular clouds. Past observations have indeed consistently pointed towards a more extended CI distribution but it was only recently, with the advent of large scale imaging of its ${}^3{P}_1\to$${}^3{P}_0$ transition, that its surprising ubiquity in molecular clouds has been fully revealed. In the present work we show that under {\it typical} ISM conditions such an ubiquity is inevitable because of well known dynamic and non-equilibrium chemistry processes maintaining a significant [C]/[${}^{12}$CO] abundance throughout Giant Molecular Clouds during their lifetime. These processes are more intense in star-forming environments where a larger ambient cosmic ray flux will also play an important role in boosting [C]/[${}^{12}$CO]. The resulting CI lines can be bright and effective H${}_2$ mass tracers especially for diffuse ($\sim 10^2-10^3\mathrm{c}{\mathrm{m}}^{-3}$) gas while in UV-intense and/or metal-poor environments their H${}_2$-tracing capability diminishes because of large scale CII production but nevertheless remains superior to that of ${}^{12}$CO. The best place to take full advantage of CI's capacity to trace H${}_2$ is not in the low-$z$ Universe, where large atmospheric absorption at 492 and 809 GHz precludes routine observations, but at high redshifts ($\rm z\ga 1$).

Accepted for publication at the Monthly Notices of the Royal Astronomical Society (29 pages, 5 figures)

References in corpus (5)

• A median redshift of 2.4 for galaxies bright at submillimetre wavelengths
• Interferometric Observations of Powerful CO Emission from the three Submillimeter Galaxies at z=2.30, 2.51 and 3.35
• Gas and Dust in the Cloverleaf Quasar at Redshift 2.5
• Molecular Gas in the Lensed Lyman Break Galaxy cB58
• Gas and Dust in the Extremely Red Object ERO J164502+4626.4

Cited by in corpus (158)

• Molecular Gas at High Redshift
• Cool Outflows in Galaxies and their Implications
• Tracing the molecular gas in distant submillimetre galaxies via CO(1-0) imaging with the EVLA
• High-redshift star formation in the ALMA era
• An extreme proto-cluster of luminous dusty starbursts in the early Universe
• Photodissociation and X-Ray Dominated Regions
• Tracing the total molecular gas in galaxies: [CII] and the CO-dark gas
• Modelling CO formation in the turbulent interstellar medium
• Revealing the cold dust in low-metallicity environments: I - Photometry analysis of the Dwarf Galaxy Survey with Herschel
• A Survey of Atomic Carbon at High Redshift
• The Properties of the Interstellar Medium within a Star-Forming Galaxy at z=2.3
• The dust mass in Cassiopeia A from a spatially resolved Herschel analysis
• Effective destruction of CO by cosmic rays: implications for tracing H${}_2$ gas in the Universe
• ALMA observations of atomic carbon in z~4 dusty star-forming galaxies
• ALMA resolves turbulent, rotating [CII] emission in a young starburst galaxy at z=4.8
• Cosmic-ray induced destruction of CO in star-forming galaxies
• CN and HCN in Dense Interstellar Clouds
• A Survey of Atomic Carbon [C I] in High-redshift Main-Sequence Galaxies
• The ALMA Spectroscopic Survey in the HUDF: CO Excitation and Atomic Carbon in Star-Forming Galaxies at $z=1-3$
• A Simple and Accurate Network for Hydrogen and Carbon Chemistry in the ISM
• CI emission in Ultra Luminous Infrared Galaxies as a molecular gas mass tracer
• Is atomic carbon a good tracer of molecular gas in metal-poor galaxies?
• A gravitationally unstable gas disk of a starburst galaxy 12 billion years ago
• Using [CI] to probe the Interstellar Medium in z~2.5 Sub-Millimeter Galaxies
• Radio Recombination Lines in Galactic HII Regions
• Turbulent Gas in Lensed Planck-selected Starbursts at redshifts 1-3.5
• A Herschel Space Observatory Spectral Line Survey of Local Luminous Infrared Galaxies from 194 to 671 Microns
• Modelling [CI] emission from turbulent molecular clouds
• The diverse cold molecular gas contents, morphologies, and kinematics of type-2 quasars as seen by ALMA
• The properties of the interstellar medium of galaxies across time as traced by the neutral atomic carbon [CI]
• Dust, CO and [CI]: Cross-calibration of molecular gas mass tracers in metal-rich galaxies across cosmic time
• ALMA reveals starburst-like interstellar medium conditions in a compact star-forming galaxy at z ~ 2 using [CI] and CO
• The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Evolution of the molecular gas in CO-selected galaxies
• An Alternative Accurate Tracer of Molecular Clouds: The "$X_{\mathrm{CI}}$-Factor"
• ALMA [CI]${}^3{P}_1{-}^3{P}_0$ observations of NGC6240: a puzzling molecular outflow, and the role of outflows in the global ${\alpha }_{\mathrm{CO}}$ factor of (U)LIRGs
• SILCC-Zoom: H${}_2$ and CO-dark gas in molecular clouds -- The impact of feedback and magnetic fields
• Measurements of CO redshifts with Z-Spec for lensed submillimeter galaxies discovered in the H-ATLAS survey
• A Survey of the Molecular ISM Properties of Nearby Galaxies using the Herschel FTS
• Giant galaxy growing from recycled gas: ALMA maps the circumgalactic molecular medium of the Spiderweb in [CI]
• Neutral carbon and CO in 76 (U)LIRGs and starburst galaxy centers A method to determine molecular gas properties in luminous galaxies
• Planck's dusty GEMS. VI. Multi-J CO excitation and interstellar medium conditions in dusty starburst galaxies at z=2-4
• Deceptively cold dust in the massive starburst galaxy GN20 at $z\sim 4$
• Metallicity dependence of the H/H${}_2$ and C${}^{+}$/C/CO distributions in a resolved self-regulating interstellar medium
• Neutral Carbon Emission in luminous infrared galaxies The \CI\ Lines as Total Molecular Gas Tracers
• The final data release of ALLSMOG: a survey of CO in typical local low-M* star-forming galaxies
• CO emission in distant galaxies on and above the main sequence
• Molecular gas, CO, and star formation in galaxies: emergent empirical relations, feedback, and the evolution of very gas-rich systems
• New places and phases of CO-poor/CI-rich molecular gas in the Universe
• An ALMA multi-line survey of the ISM in two quasar host-companion galaxy pairs at $z>6$
• Photon dominated regions in the spiral arms of M83 and M51
• Central molecular zones in galaxies: 12CO-to-13CO ratios, carbon budget, and X factors
• Herschel/SPIRE Sub-millimeter Spectra of Local Active Galaxies
• Photodissociation Region Diagnostics Across Galactic Environments
• GMC Collisions as Triggers of Star Formation. V. Observational Signatures
• Carbon Atom Reactivity with Amorphous Solid Water: H${}_2$O Catalyzed Formation of H${}_2$CO
• Molecular line intensities as measures of cloud masses - II. Conversion factors for specific galaxy types
• Resolved neutral carbon emission in nearby galaxies: [CI] Lines as Total Molecular Gas Tracers
• ALMA Observations of Multiple-CO and C Lines Toward the Active Galactic Nucleus of NGC 7469: X-Ray-dominated Region Caught in the Act
• Planck's Dusty GEMS. VII. Atomic carbon and molecular gas in dusty starburst galaxies at z=2 to 4
• An upper limit to the variation in the fundamental constants at redshift z = 5.2
• The CO-dark molecular gas mass in 30 Doradus
• A new approach for testing variations of fundamental constants over cosmic epochs using FIR fine-structure lines
• Sub-millimetre compactness as a critical dimension to understand the Main Sequence of star-forming galaxies
• Cold gas disks in main-sequence galaxies at cosmic noon: Low turbulence, flat rotation curves, and disk-halo degeneracy
• Synthetic observations of star formation and the interstellar medium
• ALMA Finds Dew Drops in the Dusty Spider's Web
• The ALMA REBELS Survey: The Cosmic HI Gas Mass Density in Galaxies at $z\approx 7$
• A sensitive APEX and ALMA CO(1-0), CO(2-1), CO(3-2), and [CI](1-0) spectral survey of 40 local (U)LIRGs
• Atomic Carbon in APM 08279+5255 at z=3.91
• Molecular Line Observations in Two Dusty Star-Forming Galaxies at z = 6.9
• Direct measurement of the [CI] luminosity to molecular gas mass conversion factor in high-redshift star-forming galaxies
• Dust continuum, CO, and [C I] 1-0 lines: self-consistent H2 mass estimates and the possibility of globally CO-dark galaxies at $z=0.35$
• Herschel SPIRE-FTS Observations of Excited CO and [CI] in the Antennae (NGC 4038/39): Warm and Cold Molecular Gas
• Surface Diffusion of Carbon Atoms as a Driver of Interstellar Organic Chemistry
• Clumpy photon-dominated regions in Carina. I. [CI] and mid-J CO lines in two 4'x4' fields
• Atomic carbon as a powerful tracer of molecular gas in the high-redshift Universe: perspectives for ALMA
• A High-Resolution Investigation of the Multi-Phase ISM in a Galaxy during the First Two Billion Years
• Neutral versus ionized gas kinematics at z~2.6: The AGN-host starburst galaxy PKS 0529-549
• The relationship between dust and [CI] at z=1 and beyond
• The subthermal excitation of the C{\sc i} lines in the molecular gas reservoirs of galaxies: its significance and potential utility
• Dynamical cloud formation traced by atomic and molecular gas
• Extreme conditions in the molecular gas of lensed star-forming galaxies at z~3
• A cosmic stream of atomic carbon gas connected to a massive radio galaxy at redshift 3.8
• High Atomic Carbon Abundance in Molecular Clouds in the Galactic Center Region
• PDFchem: A new fast method to determine ISM properties and infer environmental parameters using probability distributions
• Bright Extragalactic ALMA Redshift Survey (BEARS) III: Detailed study of emission lines from 71 Herschel targets
• Thermal Pressures in the Interstellar Medium of the Magellanic Clouds
• A magnified view of circumnuclear star formation and feedback around an AGN at z=2.6
• Simulating the atomic and molecular content of molecular clouds using probability distributions of physical parameters
• ALMA Observations of Atomic Carbon [C I] (${{}^3\mathrm{P}}_1\to {{}^3\mathrm{P}}_0$) and Low-$J$ CO Lines in the Starburst Galaxy NGC 1808
• Methane formation in cold regions from carbon atoms and molecular hydrogen
• Dark Molecular Gas in Simulations of z~0 Disc Galaxies
• The impact of cosmic-ray attenuation on the carbon cycle emission in molecular clouds
• CO (7-6), [CI] 370 micron and [NII] 205 micron Line Emission of the QSO BRI 1335-0417 at Redshift 4.407
• An Unbiased CO Survey Toward the Northern Region of the Small Magellanic Cloud with the Atacama Compact Array. I. Overview: CO Cloud Distributions
• The cold circumgalactic environment of MAMMOTH-I: dynamically cold gas in the core of an Enormous Ly-alpha Nebula
• Molecular and atomic line surveys of galaxies II: unbiased estimates of their star formation mode
• Astrochemical Correlations in Molecular Clouds
• Quenching by gas compression and consumption: A case study of a massive radio galaxy at z = 2.57
• A Multiwavelength Study of ELAN Environments (AMUSE${}^2$): Detection of a dusty star-forming galaxy within the enormous Lyman $\alpha$ nebula at $z=2.3$ sheds light on its origin
• The Interstellar Medium Properties of Heavily Reddened Quasars & Companions at z~2.5 with ALMA & JVLA
• SPIRE Spectroscopy of Early Type Galaxies
• The Carbon-to-H${}_2$, CO-to-H${}_2$ Conversion Factors and Carbon Abundance on Kiloparsec Scales in Nearby Galaxies
• Analysis of the Herschel/HEXOS Spectral Survey Towards Orion South: A massive protostellar envelope with strong external irradiation
• ALMA [CI] observations toward the central region of a Seyfert galaxy NGC 613
• Neutral carbon and highly excited CO in a massive star-forming main sequence galaxy at z=2.2
• The ramp-up of interstellar medium enrichment at z>4
• Planck's Dusty GEMS. II. Extended [CII] emission and absorption in the Garnet at z=3.4 seen with ALMA
• The effect of active galactic nuclei on the cold interstellar medium in distant star-forming galaxies
• Observations of neutral carbon in 29 high-z lensed dusty star forming galaxies and the comparison of gas mass tracers
• Molecular and atomic line surveys of galaxies I: the dense, star-forming phase as a beacon
• Gas and dust in a z=2.8 obscured quasar
• ALMA and MUSE observations reveal a quiescent multi-phase circumgalactic medium around the z~3.6 radio galaxy 4C 19.71
• Measuring space-time variation of the fundamental constants with redshifted submillimetre transitions of neutral carbon
• Stacked Average Far-Infrared Spectrum of Dusty Star-Forming Galaxies from the Herschel/SPIRE Fourier Transform Spectrometer
• Transport of Protostellar Cosmic Rays in Turbulent Dense Cores
• Measuring the average molecular gas content of star-forming galaxies at $z=3-4$
• High resolution spectral imaging of CO(7-6), [CI](2-1) and continuum of three high-z lensed dusty star-forming galaxies using ALMA
• An ACA Survey of [CI] ${}^3{P}_1{-}^3{P}_0$, CO $J=4-3$, and Dust Continuum in Nearby U/LIRG
• The Astrochemical Impact of Cosmic Rays in Protoclusters II: CI-to-H${}_2$ and CO-to-H${}_2$ Conversion Factors
• A hyper luminous starburst at z=4.72 magnified by a lensing galaxy pair at z=1.48
• Physical conditions of the molecular gas in metal-poor galaxies
• Searching for spatial variations of alpha^2/mu in the Milky Way
• A Photodissociation Region study of NGC 4038
• The cold molecular gas in z$\gtrsim$6 quasar host galaxies
• Discovery of a [CI]-faint, CO-bright Galaxy: ALMA Observations of the Merging Galaxy NGC 6052
• A sensitive search for CO J=1-0 emission in 4C 41.17: high-excitation molecular gas at z=3.8
• Atacama Large Aperture Submillimeter Telescope (AtLAST) Science: Our Galaxy
• Revisited cold gas content with atomic carbon [C I] in z=2.5 protocluster galaxies
• Flat Rotation Curves found in Merging Dusty Starbursts at $z=2.3$ through Tilted-Ring Modeling
• The SUPERCOLD-CGM survey: \\ I. Probing the extended CO(4-3) Emission of the Circumglactic medium in a sample of 10 Enormous Ly$\alpha$ Nebulae at $z\sim 2$
• Molecular gas budget and characterization of intermediate-mass star-forming galaxies at $z\approx 2-3$
• Infrared fine-structure lines at high redshift
• Assessing the Impact of Astrochemistry on Molecular Cloud Turbulence Statistics
• Gas, dust, and the CO-to-molecular gas conversion factor in low-metallicity starbursts
• Metallicity dependence of the CO-to-H${}_2$ and the [CI]-to-H${}_2$ conversion factors in galaxies
• HYACINTH: HYdrogen And Carbon chemistry in the INTerstellar medium in Hydro simulations
• CO and Fine-Structure Lines Reveal Low Metallicity in a Stellar-Mass-Rich Galaxy at z ~ 1?
• Probing the cold and warm molecular gas in the Whirlpool Galaxy: Herschel SPIRE-FTS Observations of the central region of M51 (NGC 5194)
• Atomic Carbon in the Central Molecular Zone of the Milky Way : Possible Cosmic-ray Induced Chemistry or Time-Dependent Chemistry Associated with SNR Sagittarius A East
• The interstellar medium in Andromeda's dwarf spheroidal galaxies: II. Multi-phase gas content and ISM conditions
• A search for CI J=2--1 emission in IRAS F10214+4724
• Spatially-resolved relation between [CI] ${}^3{P}_1$-${}^3{P}_0$ and ${}^{12}$CO (1-0) in Arp 220
• ALMA view of the $\rho$ Ophiuchi A PDR with a 360-au beam: the [CI] emission originates from the plane-parallel PDR and extended gas
• Gas properties as a function of environment in the proto-supercluster Hyperion at z ~ 2.45
• Evidence for environmental effects in the $z=4.3$ protocluster core SPT2349$-$56
• Main Sequence to Starburst Transitioning Galaxies: Gamma-ray Burst Hosts at $z\sim 2$
• Extremely Low Molecular Gas Content in the Vicinity of a Red Nugget Galaxy at $z=1.91$
• "Dust Giant": Extended and Clumpy Star-Formation in a Massive Dusty Galaxy at $z=1.38$
• Deep kiloparsec view of the molecular gas in a massive star-forming galaxy at cosmic noon
• Molecular gas content and high excitation of a massive main-sequence galaxy at z = 3
• [C I] and [C II] emission in the circumstellar envelope of IRC +10216 I. Observational data and NLTE modeling of the [C I] emission
• ALMA High-J CO Spectroscopy of High-Redshift Galaxies. II. 0.03" Resolution CO Kinematics Reveal Super-Eddington Accretion in a Dust-Obscured Galaxy at z=3.111
• Tight correlation of star formation with [Ci] and CO lines across cosmic time
• Measuring the HI content of individual galaxies out to the epoch of reionization with [CII]
• CO Observations of the SMC-N66 Hii Region with ALMA: Properties of Clumps along Filamentary Molecular Clouds and Possible Expansion Motion
• First Submillimeter Lights from Dome A: Tracing the Carbon Cycle in the Feedback of Massive Stars
• Low star-formation activity and low gas content of quiescent galaxies at $z=$ 3.5-4.0 constrained with ALMA