Photodissociation and X-Ray Dominated Regions

Abstract

The radiation from stars and active galactic nuclei (AGN) creates photodissociation regions (PDRs) and X-ray dominated regions (XDRs), where the chemistry or heating are dominated by far-ultraviolet (FUV) radiation or X-ray radiation, respectively. PDRs include a wide range of environments from the diffuse interstellar medium to dense star-forming regions. XDRs are found in the center of galaxies hosting AGN, in protostellar disks, and in the vicinity of X-ray binaries. In this review, we describe the dominant thermal, chemical, and radiation transfer processes in PDRs and XDRs, as well as a brief description of models and their use to analyze observations. We then present recent results from Milky Way, nearby extragalactic, and high-redshift observations. Several important results are: $\bullet$ Velocity resolved PDR lines reveal the kinematics of the neutral atomic gas and provide constraints on the stellar feedback process. Their interpretation is, however, in dispute as observations suggest a prominent role for stellar winds while they are much less important in theoretical models. $\bullet$ A significant fraction of molecular mass resides in CO-dark gas especially in low-metallicity/highly irradiated environments. $\bullet$ The CO ladder and CI/CII ratios can determine if FUV or X-rays dominate the ISM heating of extragalactic sources. $\bullet$ With ALMA, PDR and XDR tracers are now routinely detected on galactic scales over cosmic time. This makes it possible to link the star formation history of the Universe to the evolution of the physical and chemical properties of the gas.

arXiv commentSubmitted to Annual Reviews of Astronomy and Astrophysics, Volume 60, 2022

References in corpus (410)

• On the Absorption of X-rays in the Interstellar Medium
• The CO-to-H2 Conversion Factor
• A computer program for fast non-LTE analysis of interstellar line spectra
• SINGS: The SIRTF Nearby Galaxies Survey
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• The Neutral Atomic Phases of the ISM in the Galaxy
• Observations of the Icy Universe
• The UMIST database for astrochemistry 2012
• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• The Infrared Spectral Energy Distribution of Normal Star-Forming Galaxies: Calibration at Far-Infrared and Submillimeter Wavelengths
• Structure of Stationary Photodissociation Fronts
• The Dark Molecular Gas
• Far Infrared and Submillimeter Emission from Galactic and Extragalactic Photo-Dissociation Regions
• Star Clusters Across Cosmic Time
• Gas-to-Dust mass ratios in local galaxies over a 2 dex metallicity range
• The rich 6 to 9 um spectrum of interstellar PAHs
• Rapid X-ray flaring from the direction of the supermassive black hole at the Galactic Centre
• A KInetic Database for Astrochemistry (KIDA)
• The Millennium Arecibo 21-CM Absorption Line Survey. II. Properties of the Warm and Cold Neutral Media
• The photodissociation and chemistry of CO isotopologues: applications to interstellar clouds and circumstellar disks
• A model for atomic and molecular interstellar gas: The Meudon PDR code
• Photodissociation and photoionisation of atoms and molecules of astrophysical interest
• Photoelectric Emission from Interstellar Dust: Grain Charging and Gas Heating
• Non-thermal desorption from interstellar dust grains via exothermic surface reactions
• Planck Early Results: All sky temperature and dust optical depth from Planck and IRAS: Constraints on the "dark gas" in our galaxy
• The applicability of FIR fine-structure lines as Star Formation Rate tracers over wide ranges of metallicities and galaxy types
• KINGFISH -- Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel: Survey Description and Image Atlas
• Diagnostics of irradiated gas in galaxy nuclei. I: A Far-ultraviolet and X-ray dominated region code
• Regulation of Star Formation Rates in Multiphase Galactic Disks: a Thermal/Dynamical Equilibrium Model
• Far Infrared Spectroscopy of Normal Galaxies: Physical Conditions in the Interstellar Medium
• On the effect of the Cosmic Microwave Background in high-redshift (sub-)millimeter observations
• Water, O2 and Ice in Molecular Clouds
• Diagnostics of irradiated dense gas in galaxy nuclei. II. A grid of XDR and PDR models
• Cosmic-ray ionization of molecular clouds
• Little Things
• A General Model for the CO-H2 Conversion Factor in Galaxies with Applications to the Star Formation Law
• The SILCC (SImulating the LifeCycle of molecular Clouds) project: I. Chemical evolution of the supernova-driven ISM
• A 158 Micron [CII] Line Survey of Galaxies at z ~ 1 to 2: An Indicator of Star Formation in the Early Universe
• Interstellar water chemistry: from laboratory to observations
• A PDR-Code Comparison Study
• A Herschel [CII] Galactic plane survey I: the global distribution of ISM gas components
• Formation of buckminsterfullerene (C60) in interstellar space
• Black hole accretion and star formation as drivers of gas excitation and chemistry in Mrk231
• An ALMA [CII] survey of 27 quasars at z>5.94
• Photodesorption of ices I: CO, N2 and CO2
• The lifecycle of molecular clouds in nearby star-forming disc galaxies
• What controls star formation in the central 500 pc of the Galaxy?
• Ultraviolet Survey of CO and H_2 in Diffuse Molecular Clouds: The Reflection of Two Photochemistry Regimes in Abundance Relationships
• Simulating the formation of molecular clouds. II. Rapid formation from turbulent initial conditions
• Protoplanetary disc evolution and dispersal: the implications of X-ray photoevaportion
• H3+ in Diffuse Interstellar Clouds: a Tracer for the Cosmic-Ray Ionization Rate
• The Dynamics of Radiation Pressure-Dominated HII Regions
• Observations of Arp 220 using Herschel-SPIRE: An Unprecedented View of the Molecular Gas in an Extreme Star Formation Environment
• The warm gas atmosphere of the HD 100546 disk seen by Herschel (Evidence of a gas-rich, carbon-poor atmosphere?)
• Uncertainties in H2 and HD Chemistry and Cooling and their Role in Early Structure Formation
• Herschel Survey of Galactic OH+, H2O+, and H3O+: Probing the Molecular Hydrogen Fraction and Cosmic-Ray Ionization Rate
• Fast and inefficient star formation due to short-lived molecular clouds and rapid feedback
• On the Relationship Between Molecular Hydrogen and Carbon Monoxide Abundances in Molecular Clouds
• An Overview of the Dwarf Galaxy Survey
• Astrochemistry and compositions of planetary systems
• Are PAHs precursors of small hydrocarbons in Photo--Dissociation Regions? The Horsehead case
• A multi-transition HCN and HCO+ study of 12 nearby active galaxies: AGN versus SB environments
• Three-phase Interstellar medium in Galaxies Resolving Evolution with Star formation and Supernova feedback (TIGRESS): Algorithms, Fiducial model, and Convergence
• KROME - a package to embed chemistry in astrophysical simulations
• ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Survey Description
• Modeling UV Radiation Feedback from Massive Stars: II. Dispersal of Star-Forming Giant Molecular Clouds by Photoionization and Radiation Pressure
• A Compendium of Far-Infrared Line and Continuum Emission for 227 Galaxies Observed by the Infrared Space Observatory
• Warm Molecular Layers in Protoplanetary Disks
• The [C II] emission as a molecular gas mass tracer in galaxies at low and high redshift
• Dense gas in the Galactic central molecular zone is warm and heated by turbulence
• The Herschel Dwarf Galaxy Survey: I. Properties of the low-metallicity ISM from PACS spectroscopy
• Dispersal of molecular clouds by ionising radiation
• HI-to-H2 Transitions and H I Column Densities in Galaxy Star-Forming Regions
• ALMA Imaging and Gravitational Lens Models of South Pole Telescope-Selected Dusty, Star-Forming Galaxies at High Redshifts
• Morphology of the Interstellar Cooling Lines Detected by COBE
• The CI lines as tracers of molecular gas, and their prospects at high redshifts
• Detection of HCN, HCO+ and HNC in the Mrk231 molecular outflow - Dense molecular gas in the AGN wind
• Reionization Era Bright Emission Line Survey: Selection and Characterization of Luminous Interstellar Medium Reservoirs in the z>6.5 Universe
• CO-dark gas and molecular filaments in Milky Way type galaxies
• Hot and Diffuse Clouds near the Galactic Center Probed by Metastable H3+
• High-redshift star formation in the ALMA era
• The [CII] 158 micron line emission in high-redshift galaxies
• [CII] 158 $\mu$m Emission as a Star Formation Tracer
• On the [CII]-SFR relation in high redshift galaxies
• Modeling CO Emission: I. CO as a Column Density Tracer and the X-Factor in Molecular Clouds
• The Chemistry of Interstellar OH+, H2O+, and H3O+: Inferring the Cosmic Ray Ionization Rates from Observations of Molecular Ions
• Large Population of ALMA Galaxies at z>6 with Very High [OIII]88um to [CII]158um Flux Ratios: Evidence of Extremely High Ionization Parameter or PDR Deficit?
• X-ray irradiated protoplanetary disk atmospheres I: Predicted emission line spectrum and photoevaporation
• [CII] 158$\mu$m Emission and Metallicity in PDRs
• Some empirical estimates of the H2 formation rate in photon-dominated regions
• Interstellar OH+, H2O+ and H3O+ along the sight-line to G10.6-0.4
• Discovery of a superluminal Fe K echo at the Galactic Center: The glorious past of Sgr A* preserved by molecular clouds
• Collisional Excitation of the [CII] Fine Structure Transition in Interstellar Clouds
• Tracing the total molecular gas in galaxies: [CII] and the CO-dark gas
• Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
• The ALPINE-ALMA [CII] survey: Star-formation-driven outflows and circumgalactic enrichment in the early Universe
• Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. II. On the Generality of Triggered Star Formation
• The nature of the [CII] emission in dusty star-forming galaxies from the SPT survey
• A Herschel [C II] Galactic plane survey II: CO-dark H2 in clouds
• TreeCol: a novel approach to estimating column densities in astrophysical simulations
• Star Formation in Extreme Environments: The Effects of Cosmic Rays and Mechanical Heating
• Surface chemistry in the interstellar medium - I - H2 formation by Langmuir-Hinshelwood and Eley-Rideal mechanisms
• The cosmic ray ionization rate in the Galactic disk, as determined from observations of molecular ions
• The thermal state of molecular clouds in the Galactic Center: evidence for non-photon-driven heating
• The Role of Stellar Feedback in the Dynamics of HII Regions
• The reliability of [CII] as a star formation rate indicator
• Kiloparsec-scale gaseous clumps and star formation at $z=5-7$
• Interstellar Hydrides
• Dense gas in luminous infrared galaxies
• HI Narrow Self-Absorption in Dark Clouds: Correlations with Molecular Gas and Implications for Cloud Evolution and Star Formation
• Ubiquitous argonium (ArH${}^{+}$) in the diffuse interstellar medium -- a molecular tracer of almost purely atomic gas
• The chemistry of vibrationally excited H2 in the interstellar medium
• Compression and ablation of the photo-irradiated cloud the Orion Bar
• Isotopic fractionation of carbon, deuterium and nitrogen : a full chemical study
• Water formation at low temperatures by surface O2 hydrogenation II: the reaction network
• Deep into the structure of the first galaxies: SERRA views
• First Identification of 10-kpc Scale [CII] 158um Halos around Star-Forming Galaxies at z=5-7
• A Dynamical Model for the Formation of Gas Rings and Episodic Starbursts Near Galactic Centres
• Electron-Ion Recombination on Grains and Polycyclic Aromatic Hydrocarbons
• X-ray chemistry in envelopes around young stellar objects
• Disruption of the Orion Molecular Core 1 by the stellar wind of the massive star ${\theta }^1$ Ori C
• Molecules as tracers of galaxy evolution: an EMIR survey. I. Presentation of the data and first results
• SILCC-Zoom: The dynamical and chemical evolution of molecular clouds
• Models of Chemistry, Thermal Balance and Infrared Spectra from Intermediate-Aged Disks around G and K stars
• Zooming on the internal structure of $z\simeq 6$ galaxies
• The H II Region/PDR Connection: Self-Consistent Calculations of Physical Conditions in Star-Forming Regions
• Molecular Hydrogen in Star-forming regions: implementation of its micro-physics in Cloudy
• Molecular line intensities as measures of cloud masses - I. Sensitivity of CO emissions to physical parameter variations
• Comparative study of CH+ and SH+ absorption lines observed towards distant star-forming regions
• Radiation thermo-chemical models of protoplanetary disks II. Line diagnostics
• CN and HCN in Dense Interstellar Clouds
• Cosmic-ray induced destruction of CO in star-forming galaxies
• A Herschel [CII] Galactic plane survey III: [CII] as a tracer of star formation
• Interpreting ALMA Observations of the ISM During the Epoch of Reionisation
• The Spitzer Survey of the Small Magellanic Cloud (S3MC): Insights into the Life-Cycle of Polycyclic Aromatic Hydrocarbons
• Molecular Cloud Structure in the Magellanic Clouds: Effect of Metallicity
• The 21-SPONGE HI Absorption Line Survey II: The temperature of Galactic HI
• Velocity-resolved [CII] emission and [CII]/FIR Mapping along Orion with Herschel
• ALMA Multi-line Imaging of the Nearby Starburst Galaxy NGC 253
• The ALPINE-ALMA [CII] survey: Molecular gas budget in the Early Universe as traced by [CII]
• 3D-PDR: A new three-dimensional astrochemistry code for treating Photodissociation Regions
• The ALMA Spectroscopic Survey in the HUDF: CO Excitation and Atomic Carbon in Star-Forming Galaxies at $z=1-3$
• The far-IR spectrum of Sagittarius B2 region: Extended molecular absorption, photodissociation and photoionization
• Modelling Herschel observations of hot molecular gas emission from embedded low-mass protostars
• The Spitzer View of Low-Metallicity Star Formation: III. Fine Structure Lines, Aromatic Features, and Molecules
• Sulphur-bearing molecules in diffuse molecular clouds: new results from SOFIA/GREAT and the IRAM 30 m telescope
• Structure and Feedback in 30 Doradus II. Structure and Chemical Abundances
• A Simple and Accurate Network for Hydrogen and Carbon Chemistry in the ISM
• Missing [CII] emission from early galaxies
• Isotope selective photodissociation of N2 by the interstellar radiation field and cosmic rays
• Time Dependence of the Ultraviolet Radiation Field in the Local Interstellar Medium
• The Origins of [CII] Emission in Local Star-forming Galaxies
• The Spatially Resolved [CII] Cooling Line Deficit in Galaxies
• Simulations of the Milky Way's central molecular zone -- I. Gas dynamics
• Non-Equilibrium Photodissociation Regions: Ionization-Dissociation Fronts
• The Herschel Dwarf Galaxy Survey: II. Physical conditions, origin of [CII] emission, and porosity of the multiphase low-metallicity ISM
• The full infrared spectrum of molecular hydrogen
• HCN/HNC intensity ratio: a new chemical thermometer for the molecular ISM
• The chemistry of ions in the Orion Bar I. - CH+, SH+, and CF+: The effect of high electron density and vibrationally excited H2 in a warm PDR surface
• SHINING, A Survey of Far Infrared Lines in Nearby Galaxies. II: Line-Deficit Models, AGN impact, [CII]-SFR Scaling Relations, and Mass-Metallicity Relation in (U)LIRGS
• A physical model for [CII] line emission from galaxies
• Diagnostic Line Emission from EUV and X-ray Illuminated Disks and Shocks around Low Mass stars
• Origin of the hot gas in low-mass protostars: Herschel-PACS spectroscopy of HH 46
• Overluminous HNC Line Emission in Arp220, NGC4418 and Mrk231 - Global IR Pumping or XDRs?
• Efficiently Cooled Stellar Wind Bubbles in Turbulent Clouds I. Fractal Theory and Application to Star-Forming Clouds
• Structure of photodissociation fronts in star-forming regions revealed by observations of high-J CO emission lines with Herschel
• The Ratio of Ortho- to Para-H2 in Photodissociation Regions
• Resolving the Far-IR Line Deficit: Photoelectric Heating and Far-IR Line Cooling in NGC 1097 and NGC 4559
• Cosmic-ray and X-ray Heating of Interstellar Clouds and Protoplanetary Disks
• Grain size distributions and photo-electric heating in ionized media
• Gone With the Wind: Where is the Missing Stellar Wind Energy from Massive Star Clusters?
• The Mopra Southern Galactic Plane CO Survey
• The PAH emission characteristics of the reflection nebula NGC2023
• Is atomic carbon a good tracer of molecular gas in metal-poor galaxies?
• Irradiated ISM: Discriminating between Cosmic Rays and X-rays
• Surface chemistry in the Interstellar Medium II. ${\mathrm{H}}_2$ formation on dust with random temperature fluctuations
• SIGAME simulations of the [CII], [OI] and [OIII] line emission from star forming galaxies at z ~ 6
• [CII] absorption and emission in the diffuse interstellar medium across the Galactic Plane
• ALMA Resolves 30 Doradus: Sub-parsec Molecular Cloud Structure Near the Closest Super-Star Cluster
• Tracing the formation of molecular clouds via [CII], [CI] and CO emission
• Strong [CII] emission at high redshift
• Revealing the Photodissociation Region: Hubble Space Telescope/NICMOS Imaging of NGC 7027
• Dark gas in the solar neighnorhood from extinction data
• Molecular gas chemistry in AGN. II. High-resolution imaging of SiO emission in NGC1068: shocks or XDR?
• The Survey of Water and Ammonia in the Galactic Center (SWAG): Molecular Cloud Evolution in the Central Molecular Zone
• First interstellar detection of OH+
• Mechanical feedback in the molecular ISM of luminous IR galaxies
• Dense Gas, Dynamical Equilibrium Pressure, and Star Formation in Nearby Star-Forming Galaxies
• Probing Cosmic Dawn with Emission Lines: Predicting Infrared and Nebular Line Emission for ALMA and JWST
• Chemical Rates on Small Grains and PAHs: C^+ Recombination and H_2 Formation
• Physical Properties of Molecular Clouds at 2 parsec Resolution in the Low-Metallicity Dwarf Galaxy NGC 6822 and the Milky Way
• Photodissociation of interstellar N2
• Modelling [CI] emission from turbulent molecular clouds
• Chemical probes of turbulence in the diffuse medium: the TDR model
• [CII] at 158 mic as a star formation tracer in late-type galaxies
• Molecular gas in three z~7 quasar host galaxies
• The Warm Molecular Gas Around the Cloverleaf Quasar
• The penetration of FUV radiation into molecular clouds
• The Structure of a Low-Metallicity Giant Molecular Cloud Complex
• Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample
• Excitation Mechanisms for HCN (1-0) and HCO+ (1-0) in Galaxies from the Great Observatories All-sky LIRG Survey
• Efficiently Cooled Stellar Wind Bubbles in Turbulent Clouds II. Validation of Theory with Hydrodynamic Simulations
• ISO observations of the Galactic center Interstellar Medium: neutral gas and dust
• The properties of the interstellar medium of galaxies across time as traced by the neutral atomic carbon [CI]
• The dynamical evolution of molecular clouds near the Galactic Centre - II. Spatial structure and kinematics of simulated clouds
• Physical conditions in the central molecular zone inferred by H3+
• A kiloparsec view of a typical star-forming galaxy when the Universe was ~1 Gyr old. Part I. Outflow, halo, and interstellar medium properties
• Herschel-SPIRE Imaging Spectroscopy of Molecular Gas in M82
• Herschel-PACS Observations of Far-IR CO Line Emission in NGC 1068: Highly Excited Molecular Gas in the Circumnuclear Disk
• Multi-molecule ALMA observations towards the Seyfert 1 galaxy NGC 1097
• Chemistry in Cosmic-Ray Dominated Regions (CRDRs)
• The Transition from Atomic to Molecular Hydrogen in Interstellar Clouds: 21cm Signature of the Evolution of Cold Atomic Hydrogen in Dense Clouds
• Physical Characterization of an Unlensed Dusty Star-Forming Galaxy at $z=5.85$
• ALMA reveals starburst-like interstellar medium conditions in a compact star-forming galaxy at z ~ 2 using [CI] and CO
• SHINING, A Survey of Far Infrared Lines in Nearby Galaxies. I: Survey Description, Observational Trends, and Line Diagnostics
• Nitrogen isotope fractionation in protoplanetary disks
• Thermal Phases of the Neutral Atomic Interstellar Medium -- from Solar Metallicity to Primordial Gas
• Expanding bubbles in Orion A: [CII] observations of M42, M43, and NGC 1977
• An Alternative Accurate Tracer of Molecular Clouds: The "$X_{\mathrm{CI}}$-Factor"
• CO line emission from galaxies in the Epoch of Reionization
• The art of modeling CO, [CI], and [CII] in cosmological galaxy formation models
• Carbon Fractionation in PDRs
• The Central 300 pc of the Galaxy probed by infrared spectra of H${}_3^{+}$ and CO: part I. Predominance of warm and diffuse gas and high H${}_2$ ionization rate
• Water absorption in Galactic translucent clouds: conditions and history of the gas derived from Herschel/HIFI PRISMAS observations
• SILCC-Zoom: H${}_2$ and CO-dark gas in molecular clouds -- The impact of feedback and magnetic fields
• Chemical Modelling of Young Stellar Objects, I. Method and Benchmarks
• Strong C+ emission in galaxies at z~1-2: Evidence for cold flow accretion powered star formation in the early Universe
• Submillimeter-HCN Diagram for an Energy Diagnostics in the Centers of Galaxies
• Electron Excitation of High Dipole Moment Molecules Reexamined
• Starbursting [O III] emitters and quiescent [C II] emitters in the reionization era
• The ${}^{12}$CO/${}^{13}$CO ratio in turbulent molecular clouds
• Spatially Resolved Interstellar Medium and Highly-Excited Dense Molecular Gas in the Most Luminous Quasar at z=6.327
• Forces on Dust Grains Exposed to Anisotropic Interstellar Radiation Fields
• First CO(17-16) emission line detected in a z > 6 quasar
• FIR line emission from high redshift galaxies
• A Hard X-ray Test of HCN Enhancements as a Tracer of Embedded Black Hole Growth
• PACS and SPIRE photometer maps of M33: First results of the Herschel M33 extended survey (HERM33ES)
• GREAT confirms transient nature of the circumnuclear disk
• Parameterizing the interstellar dust temperature
• Widespread HCO emission in the M82's nuclear starburst
• H2 distribution during formation of multiphase molecular clouds
• Which feedback mechanisms dominate in the high-pressure environment of the Central Molecular Zone?
• Metallicity dependence of the H/H${}_2$ and C${}^{+}$/C/CO distributions in a resolved self-regulating interstellar medium
• Properties of cold and warm HI gas phases derived from a Gaussian decomposition of HI4PI data
• The 3D Velocity Structure of the Thick Disk from SPM4 and RAVE DR2
• The HI-to-H2 Transition in a Turbulent Medium
• Chemical complexity in the Horsehead photodissociation region
• Modeling The Molecular Composition in an AGN Disk
• FEEDBACK: a SOFIA Legacy Program to Study Stellar Feedback in Regions of Massive Star Formation
• Multidimensional chemical modelling, II. Irradiated outflow walls
• Spatial variation of the cooling lines in the Orion Bar from Herschel/PACS
• Outflows and extended [CII] halos in high redshift galaxies
• Velocity dispersion in the interstellar medium of early galaxies
• Molecular gas in spiral galaxies: a new warm phase at large galactocentric distances?
• An ALMA multi-line survey of the ISM in two quasar host-companion galaxy pairs at $z>6$
• Chemical stratification in the Orion Bar: JCMT Spectral Legacy Survey observations
• Regional variations in the dense gas heating and cooling in M51 from Herschel far-infrared spectroscopy
• Radiative and mechanical feedback into the molecular gas of NGC 253
• Predicting FIR lines from simulated galaxies
• UV-driven chemistry in simulations of the interstellar medium. I. Post-processed chemistry with the Meudon PDR code
• A milestone toward understanding PDR properties in the extreme environment of LMC-30Dor
• A clumpy-cloud PDR model of the global far-infrared line emission of the Milky Way
• Photon dominated regions in the spiral arms of M83 and M51
• The Orion HII Region and the Orion Bar in the Mid-Infrared
• Production of atomic hydrogen by cosmic rays in dark clouds
• Atomic and Molecular Carbon as a Tracer of Translucent Clouds
• Central molecular zones in galaxies: 12CO-to-13CO ratios, carbon budget, and X factors
• Continuum and line modelling of discs around young stars. I. 300000 disc models for Herschel/GASPS
• Kinetic Monte Carlo Studies of Hydrogen Abstraction from Graphite
• Photoelectric cross-sections of gas and dust in protoplanetary disks
• Large-scale mapping observations of the CI(3P1-3P0) and CO(J=3-2) lines toward the Orion A molecular cloud
• Photodissociation Region Diagnostics Across Galactic Environments
• [12CII] and [13CII] 158 mum emission from NGC 2024: Large column densities of ionized carbon
• Interaction of Close-in Planets with the Magnetosphere of their Host Stars. II. Super-Earths as Unipolar Inductors and their Orbital Evolution
• Spectroscopically resolved far-IR observations of the massive star-forming region G5.89--0.39
• [CII] emission from L1630 in the Orion B molecular cloud
• The chemistry of interstellar argonium and other probes of the molecular fraction in diffuse clouds
• On the Detection of High Redshift Black Holes with ALMA through CO and H2 Emission
• X-ray photodesorption from water ice in protoplanetary disks and X-ray dominated regions
• Low star formation efficiency in typical galaxies at z=5-6
• A Far Ultraviolet Spectroscopic Explorer Survey of Interstellar Molecular Hydrogen in the Galactic Disk
• Forced turbulence in thermally bistable gas: A parameter study
• First Results from the $Herschel$ and ALMA Spectroscopic Surveys of the SMC: The Relationship Between [CII]-bright Gas and CO-bright Gas at Low Metallicity
• Full SED fitting with the KOSMA-τ PDR code - I. Dust modelling
• Modelling clumpy PDRs in 3D - Understanding the Orion Bar stratification
• CII in the Interstellar Medium: Excitation by H2 Revisited
• PDR Model Mapping of Physical Conditions via Spitzer/IRS Spectroscopy of H2: Theoretical Success toward NGC 2023-South
• Neutral gas heating by X-rays in primitive galaxies: Infrared observations of IZw18 with Herschel
• Sensitivity of PDR Calculations to Microphysical Details
• 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
• Diagnostics of the molecular component of PDRs with mechanical heating. II: line intensities and ratios
• Impact of X-rays on CO emission from high-z galaxies
• Full of Orions: a 200-pc mapping of the interstellar medium in the redshift-3 lensed dusty star-forming galaxy SDP.81
• [CII] 158 μm self-absorption and optical depth effects
• ALMA Astrochemical Observations of the Infrared-Luminous Merger NGC 3256
• HIFI Spectroscopy of ${\mathrm{H}}_2\mathrm{O}$ submm Lines in Nuclei of Actively Star Forming Galaxies
• [C II] emission from galactic nuclei in the presence of X-rays
• WARPFIELD-EMP: The Self-Consistent Prediction of Emission Lines from Evolving HII Regions in Dense Molecular Clouds
• Diffusive Versus Free-Streaming Cosmic Ray Transport in Molecular Clouds
• The CO-dark molecular gas mass in 30 Doradus
• Detection of extragalactic H3O+
• SOFIA FEEDBACK survey: exploring the dynamics of the stellar wind driven shell of RCW 49
• Photoevaporation of Jeans-unstable molecular clumps
• Bottlenecks to interstellar sulfur chemistry: Sulfur-bearing hydrides in UV-illuminated gas and grains
• 3D chemical structure of diffuse turbulent ISM. I. Statistics of the HI-to-H${}_2$ transition
• Constraining physical conditions for the PDR of Trumpler 14 in the Carina Nebula
• Optically thick HI does not dominate dark gas in the local ISM
• The role of C/O in nitrile astrochemistry in PDRs and planet-forming disks
• WISH VI. Constraints on UV and X-ray irradiation from a survey of hydrides in low- to high-mass YSOs
• Probing the full CO spectral line energy distribution (SLED) in the nuclear region of a quasar-starburst system at $z=6.003$
• FUV and X-ray irradiated protoplanetary disks: a grid of models II - Gas diagnostic line emission
• Physical Conditions of Molecular Gas in the Galactic Center
• Far-infrared study of tracers of oxygen chemistry in diffuse clouds
• Model-Free Multi-Probe Lensing Reconstruction of Cluster Mass Profiles
• Effects of turbulent diffusion on the chemistry of diffuse clouds
• HI filaments are cold and associated with dark molecular gas. HI4PI based estimates of the local diffuse CO-dark H2 distribution
• Synthetic [CII] emission maps of a simulated molecular cloud in formation
• Efficient ortho-para conversion of H2 on interstellar grain surfaces
• X-ray radiative transfer in protoplanetary disks - The role of dust and X-ray background fields
• ALMA Spatially-resolved Dense Molecular Gas Survey of Nearby Ultraluminous Infrared Galaxies
• Herschel / HIFI spectral line survey of the Orion Bar - Temperature and density differentiation near the PDR surface
• Velocity resolved [CII], [CI], and CO observations of the N159 star-forming region in the Large Magellanic Cloud: a complex velocity structure and variation of the column densities
• X-ray induced chemistry of water and related molecules in low-mass protostellar envelopes
• Velocity profiles of [CII], [CI], CO, and [OI] and physical conditions in four star-forming regions in the Large Magellanic Cloud
• Effect of the heating rate on the stability of the three-phase interstellar medium
• Imaging the Molecular Interstellar Medium in a Gravitationally Lensed Star-forming Galaxy at z=5.7
• CO excitation in the Seyfert galaxy NGC 34: stars, shock or AGN driven?
• Approaching hell's kitchen: Molecular daredevil clouds in the vicinity of Sgr A*
• H3O+ Line Emission from Starbursts and AGNs
• Chemical Abundances in a Turbulent Medium -- H${}_2$, OH${}^{+}$, H${}_2$O${}^{+}$, ArH${}^{+}$
• Molecular gas heating in Arp 299
• Herschel Spectroscopic Observations of LITTLE THINGS Dwarf Galaxies
• Molecular globules in the Veil bubble of Orion. IRAM 30m 12CO, 13CO, and C18O 2-1 expanded maps of Orion A
• Modelling the ArH${}^{+}$ emission from the Crab Nebula
• The interstellar medium of the Antennae Galaxies
• Formation of interstellar SH${}^{+}$ from vibrationally excited H${}_2$: Quantum study of S${}^{+}$ + H${}_2$ $\rightleftarrows$ SH${}^{+}$ + H reactions and inelastic collisions
• Non-Equilibrium Chemistry and Destruction of CO by X-ray Flares
• Photoinduced polycyclic aromatic hydrocarbon dehydrogenation: Molecular hydrogen formation in dense PDRs
• Spectral shifting strongly constrains molecular cloud disruption by radiation pressure on dust
• Molecular transitions as probes of the physical conditions of extragalactic environments
• CO excitation in the Seyfert galaxy NGC7130
• Kinematics and properties of the Central Molecular Zone as probed with [C II]
• Optically Thick [O I] and [C II] Emission Towards NGC 6334 A
• A Herschel/HIFI Legacy Survey of HF and H2O in the Galaxy: Probing Diffuse Molecular Cloud Chemistry
• Extended Carbon Line Emission in the Galaxy: Searching for Dark Molecular Gas along the G328 Sightline
• The CH+ Abundance in Turbulent, Diffuse Molecular Clouds
• Characterizing the Multi-Phase Origin of [CII] Emission in M101 and NGC 6946 with Velocity Resolved Spectroscopy
• The PDR structure and kinematics around the compact HII regions S235A and S235C with [CII], [13CII], [OI] and HCO+ line profiles
• Radiative and mechanical feedback into the molecular gas in the Large Magellanic Cloud. II. 30 Doradus
• Surface chemistry in photodissociation regions
• Predicting HCN, HCO+, multi-transition CO, and dust emission of star-forming galaxies From local spiral and ultraluminous infrared galaxies to high-z star-forming and submillimeter galaxies
• A thorough view of the nuclear region of NGC 253 - Combined Herschel, SOFIA and APEX dataset
• First detection of the 448 GHz ortho-H2O line at high redshift: probing the structure of a starburst nucleus at z = 3.63
• The Molecular ISM in the Super Star Clusters of the Starburst NGC 253
• HIFI observations of warm gas in DR21: Shock versus radiative heating
• Extended warm and dense gas towards W49A: starburst conditions in our Galaxy?
• Carbon radio recombination lines from gigahertz to megahertz frequencies towards Orion A
• The ALMA Spectroscopic Survey in the HUDF: A Search for [CII] Emitters at $6\le z\le 8$
• Radiative and mechanical feedback into the molecular gas in the Large Magellanic Cloud. I. N159W
• Excitation of the molecular gas in the nuclear region of M82
• C+/H2 Gas in Star-Forming Clouds and Galaxies
• Probing ISM Structure in Trumpler 14 & Carina I Using The Stratospheric Terahertz Observatory 2
• Turbulent dissipation, CH${}^{+}$ abundance, H${}_2$ line luminosities, and polarization in the cold neutral medium
• First Extragalactic Detection of Far-Infrared CH Rotational Lines from the Herschel Space Observatory
• The Origin of [CII] 158um Emission toward the HII Region Complex S235
• Opening the Treasure Chest in Carina
• Rise of the Titans: Gas Excitation and Feedback in a Binary Hyper-Luminous Dusty Starburst Galaxy at z~6
• [CII] $158\mu \mathrm{m}$ line emission from Orion A. I. A template for extragalactic studies?
• HyGAL: Characterizing the Galactic ISM with observations of hydrides and other small molecules -- I. Survey description and a first look toward W3(OH), W3 IRS5 and NGC 7538 IRS1
• The origin of the [C II] emission in the S140 PDRs - new insights from HIFI
• HI-to-H${}_2$ Transitions in Dust-Free Interstellar Gas
• [C II] and [N II] from dense ionized regions in the Galaxy
• AGN X-ray irradiation of CO gas in NGC 2110 revealed by $Chandra$ and ALMA
• CO Spectral Line Energy Distributions in Galactic Sources: Empirical Interpretation of Extragalactic Observations
• The effect of active galactic nuclei on the cold interstellar medium in distant star-forming galaxies
• Planck's Dusty GEMS. VIII. Dense-gas reservoirs in the most active dusty starbursts at z~3
• Upper limits to interstellar NH+ and para-NH2- abundances. Herschel-HIFI observations towards Sgr B2 (M) and G10.6-0.4 (W31C)
• Enhanced H2O formation through dust grain chemistry in X-ray exposed environments
• The fine structure line deficit in S 140
• Vibrationally excited HC3N emission in NGC1068: Tracing the recent star formation in the starburst ring
• The Chemical Effects of Mutual Shielding in Photon Dominated Regions
• The Structure of Dark Molecular Gas in the Galaxy -- II. Physical State of "CO-Dark" Gas in the Perseus Arm
• The Astrochemical Impact of Cosmic Rays in Protoclusters II: CI-to-H${}_2$ and CO-to-H${}_2$ Conversion Factors
• Herschel PACS and SPIRE spectroscopy of the Photodissociation Regions associated with S 106 and IRAS 23133+6050
• Velocity resolved [CII] spectroscopy of the center and the BCLMP302 region of M33 (HerM33es)
• Mid-J CO Shock Tracing Observations of Infrared Dark Clouds III: SLED fitting
• Observation and calibration strategies for large-scale multi-beam velocity-resolved mapping of the [CII] emission in the Orion molecular cloud
• Molecular and Ionized Hydrogen in 30 Doradus. I. Imaging Observations
• Supersonic turbulence in Giant HII Regions: clues from 30 Doradus
• Extending the view of ArH+ chemistry in diffuse clouds
• Dense and warm neutral gas in BR1202-0725 at z = 4.7 as traced by the [O I] 145 um line
• Disentangling the excitation conditions of the dense gas in M17 SW
• Electron-impact excitation of diatomic hydride cations II: OH${}^{+}$ and SH${}^{+}$
• Modeling Time Dependent Water Chemistry Due to Powerful X-ray Flares from T-Tauri Stars
• Globules and pillars in Cygnus X III. Herschel and upGREAT/SOFIA far-infrared spectroscopy of the globule IRAS 20319+3958 inCygnus X
• Gas and dust cooling along the major axis of M33 (HerM33es) -- Herschel/PACS [CII] and [OI] observations
• Merged H/H2 and C+/C/CO transitions in the Orion Bar
• The CO universe: Modelling CO emission and H${}_2$ abundance in cosmological galaxy formation simulations
• The distribution of ionized, atomic and PDR gas around S1 in Rho Ophiuchus
• The Case for Thermalization as a Contributor to the [CII] Deficit
• Etching glass in the early Universe: Luminous HF and water emission in a QSO-SMG pair at z=4.7
• A PDR model for the FIR mid-$J$ CO ladder with universal rotational temperature in star forming region
• A SOFIA Survey of [CII] in the galaxy M51 II. [CII] and CO kinematics across spiral arms
• Impact of an Active Sgr A* on the Synthesis of Water and Organic Molecules Throughout the Milky Way
• SOFIA-upGREAT imaging spectroscopy of the [C II] 158um fine structure line of the Sgr B region in the Galactic center
• Observed CN and HCN intensity ratios exhibit subtle variations in extreme galaxy environments
• Probing the cold and warm molecular gas in the Whirlpool Galaxy: Herschel SPIRE-FTS Observations of the central region of M51 (NGC 5194)
• Dynamical Properties of Molecular-forming Gas Clumps in Galaxies at the Epoch of Reionization
• The multi-phase ISM in the nearby composite AGN-SB galaxy NGC 4945: large (parsecs) scale mechanical heating

Cited by in corpus (95)

• PDRs4All III: JWST's NIR spectroscopic view of the Orion Bar
• Regular rotation and low turbulence in a diverse sample of z ~ 4.5 galaxies observed with ALMA
• Dynamical characterization of galaxies up to $z\sim 7$
• Introducing TIGRESS-NCR: I. Co-Regulation of the Multiphase Interstellar Medium and Star Formation Rates
• CONCERTO: High-fidelity simulation of millimeter line emissions of galaxies and [CII] intensity mapping
• Photochemistry and Heating/Cooling of the Multiphase Interstellar Medium with UV Radiative Transfer for Magnetohydrodynamic Simulations
• PHANGS-JWST First Results: Variations in PAH Fraction as a Function of ISM Phase and Metallicity
• Testing AGN outflow and accretion models with CIV and HeII emission line demographics in z=2 quasars
• PDRs4All II: JWST's NIR and MIR imaging view of the Orion Nebula
• JWST: Deuterated PAHs, PAH-nitriles, and PAH Overtone and Combination Bands I: Program Description and First Look
• The PhotoDissociation Region Toolbox: Software and Models for Astrophysical Analysis
• The ALMA-ALPAKA survey II. Evolution of turbulence in galaxy disks across cosmic time: difference between cold and warm gas
• Photoevaporation of protoplanetary discs with PLUTO+PRIZMO I. Lower X-ray-driven mass-loss rates due to enhanced cooling
• Star Formation and Molecular Gas Diagnostics with Mid- and Far-Infrared Emission
• PHANGS-JWST First Results: The Influence of Stellar Clusters on PAHs in Nearby Galaxies
• 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
• Bright Extragalactic ALMA Redshift Survey (BEARS) III: Detailed study of emission lines from 71 Herschel targets
• The ALMA-CRISTAL survey: Gas, dust, and stars in star-forming galaxies when the Universe was ~1 Gyr old I. Survey overview and case studies
• High resolution modeling of [CII], [CI], [OIII] and CO line emission from the ISM and CGM of a star forming galaxy at z ~ 6.5
• The ALMA-CRISTAL Survey: Spatial extent of [CII] line emission in star-forming galaxies at $z=4-6$
• Self-consistent dust and non-LTE line radiative transfer with SKIRT
• High angular resolution near-IR view of the Orion Bar revealed by Keck/NIRC2
• PHANGS-JWST First Results: Stellar Feedback-Driven Excitation and Dissociation of Molecular Gas in the Starburst Ring of NGC 1365?
• PDRs4All XI. Detection of infrared CH${}^{+}$ and CH${}_3^{+}$ rovibrational emission in the Orion Bar and disk d203-506: evidence of chemical pumping
• The extremely sharp transition between molecular and ionized gas in the Horsehead nebula
• The SOFIA FEEDBACK Legacy Survey: Rapid molecular cloud dispersal in RCW 79
• OH mid-infrared emission as a diagnostic of H${}_2$O UV photodissociation. II. Application to interstellar PDRs
• The [CII] 158 $\mu$m emission line as a gas mass tracer in high redshift quiescent galaxies
• The ALMA-CRISTAL survey: Resolved kinematic studies of main sequence star-forming galaxies at 4<z<6
• PDRs4All. XII. FUV-driven formation of hydrocarbon radicals and their relation with PAHs
• SOFIA FEEDBACK Survey: The Pillars of Creation in [C II] and Molecular Lines
• Diagnosing the interstellar medium of galaxies with far-infrared emission lines II. [C II], [O I], [O III], [N II] and [N III] up to z=6
• The Karl G. Jansky Very Large Array Local Group L-band Survey (LGLBS)
• Mapping NGC 7027 in New Light: CO${}^{+}$ and HCO${}^{+}$ Emission Reveal Its Photon- and X-ray-Dominated Regions
• Atacama Large Aperture Submillimeter Telescope (AtLAST) Science: Our Galaxy
• JWST observations of the Horsehead photon-dominated region I. First results from multi-band near- and mid-infrared imaging
• The extremely X-ray luminous radio-loud quasar CFHQS J142952+544717 at $z=6.18$ under Chandra high-angular resolution lens
• PDRs4All XVI. Tracing aromatic infrared band characteristics in photodissociation region spectra with PAHFIT in the JWST era
• Infrared fine-structure lines at high redshift
• CI and CO in Nearby Spiral Galaxies -- I. Line Ratio and Abundance Variations at ~ 200 pc Scales
• Cosmic Ray Ionization of Low-Excitation Lines in Active Galactic Nuclei and Starburst Galaxies
• Metallicity dependence of the CO-to-H${}_2$ and the [CI]-to-H${}_2$ conversion factors in galaxies
• A nearly constant CN/HCN line ratio in nearby galaxies: CN as a new tracer of dense gas
• Spritz is sparkling: simulated CO and [CII] luminosities
• H${}_3^{+}$ absorption and emission in local U/LIRGs with JWST/NIRSpec: Evidence for high H${}_2$ ionization rates
• PDRs4All XIII. Empirical prescriptions for the interpretation of JWST imaging observations of star-forming regions
• Detection of the [O I] 63 $\mu$m emission line from the $z=6.04$ quasar J2054-0005
• Spatially resolved [CII]-gas conversion factor in early galaxies
• New routes for PN destruction and formation in the ISM via neutral-neutral gas-phase reactions and an extended database for reactions involving phosphorus
• Multiline observations of hydrogen, helium, and carbon radio-recombination lines toward Orion A: A detailed dynamical study and direct determination of physical conditions
• A plausible link between dynamically unsettled molecular gas and the radio jet in NGC 6328
• Observational signatures of the dust size evolution in isolated galaxy simulations
• The origin of dust polarization in the Orion Bar
• Detections of [C II] 158 $\mu$m and [O III] 88 $\mu$m in a Local Lyman Continuum Emitter, Mrk 54, and its Implications to High-redshift ALMA Studies
• Ionized Carbon in Galaxies: The [C II] 158 $\mu$m Line as a Total Molecular Gas Mass Tracer Revisited
• The ALPINE-ALMA [CII] Survey: Modelling ALMA and JWST lines to constrain the interstellar medium of $z\sim 5$ galaxies
• PDRs4All XV: CH radical and H${}_3^{+}$ molecular ion in the irradiated protoplanetary disk d203-506
• High Resolution Observations of HI in the IC 63 Reflection Nebula
• Detectability of Polycyclic Aromatic Hydrocarbons in the Atmosphere of WASP-6 b with JWST NIRSpec PRISM
• Not gone with the Wind: Survival of High-Velocity Molecular Clouds in the Galactic center
• The origin and evolution of the [CII] deficit in HII regions and star-forming molecular clouds
• NeuralPDR: Neural Differential Equations as surrogate models for Photodissociation Regions
• Tree-based solvers for adaptive mesh refinement code FLASH -- IV: An X-ray radiation scheme to couple discrete and diffuse X-ray emission sources to the thermochemistry of the interstellar medium
• The ALPINE-CRISTAL-JWST survey: spatially resolved star formation relations at $z\sim 5$
• Probing the heating of the neutral atomic interstellar medium in the Dwarf Galaxy Survey through infrared cooling lines
• High$-z$ [OI] emission lines: ColdSIM simulations and ALMA observations
• Multi-line Observations, Models, and Data Needed to Understand the Nature of UV-irradiated Interstellar Matter
• A High-resolution Far-infrared Survey to Probe Black Hole-Galaxy Co-evolution
• Cosmic-ray impact on optical and mid-infrared emission line diagnostics in NGC 5728
• A theoretical investigation of far-infrared fine structure lines at $z>6$ and of the origin of the [OIII]88/[CII]158 enhancement
• An ALMA Band 7 survey of SDSS/Herschel quasars in Stripe 82: I. The properties of the 870 micron counterparts
• Systematic Study of the Inner Structure of Molecular Tori in Nearby U/LIRGs using Velocity Decomposition of CO Rovibrational Absorption Lines
• Physics and Chemistry of Radiation Driven Cloud Evolution. [C II] Kinematics of IC 59 and IC 63
• Molecular gas content and high excitation of a massive main-sequence galaxy at z = 3
• First detection of CF${}^{+}$ in the Large Magellanic Cloud
• 3 mm Spectroscopic Observations of Massive Star-Forming Regions with IRAM 30-m
• PDRs4All XVII: Formation and excitation of HD in photodissociation regions. Application to the Orion Bar
• The Impact of Expanding HII Regions on Filament G37:Curved Magnetic Field and Multiple Direction Material Flows
• The impact of attenuation on cosmic-ray chemistry: I. Abundances and chemical calibrators in molecular clouds
• Interstellar Medium in Extremely High Star-Formation Regions: A Prospect of Observations on the Millimetron Space Observatory
• Beetroots: spatially-regularized Bayesian inference of physical parameter maps -- Application to Orion
• Extended atomic carbon around molecular clouds
• Exploring circumstellar chemistry in X-ray emitting AGB stars
• Identifying the principal mechanism of star formation feedback
• JWST observations of photodissociation regions. IV. Carbonaceous emission band sub-components in NGC 7023 have distinct spatial distributions
• Uncovering the absorbed atomic Universe with the [OI]63um line
• Spatial distribution of organics in the Horsehead nebula: Signposts of chemistry driven by atomic carbon
• PDRs4All XVIII. JWST-NIRCam Photometric properties of protoplanetary disks in the Orion Nebula Cluster
• Diverse stages of star formation in the IRAS 18162-2048 region. Emergence of UV Feedback
• JWST observations of photodissociation regions III. Dust modelling at the illuminated edge of the Horsehead PDR
• Galaxy Activity, Torus and Outflow Survey (GATOS) X: Molecular gas clumpiness under the influence of AGN
• First Submillimeter Lights from Dome A: Tracing the Carbon Cycle in the Feedback of Massive Stars
• LMC+: Large-scale mapping of [CII] and [OIII] in the LMC molecular ridge, I. Dataset and line ratio analyses
• The ALMA View of High-Redshift Galaxy Formation