PDRs4All III: JWST's NIR spectroscopic view of the Orion Bar

Abstract

(Abridged) We investigate the impact of radiative feedback from massive stars on their natal cloud and focus on the transition from the HII region to the atomic PDR (crossing the ionisation front (IF)), and the subsequent transition to the molecular PDR (crossing the dissociation front (DF)). We use high-resolution near-IR integral field spectroscopic data from NIRSpec on JWST to observe the Orion Bar PDR as part of the PDRs4All JWST Early Release Science Program. The NIRSpec data reveal a forest of lines including, but not limited to, HeI, HI, and CI recombination lines, ionic lines, OI and NI fluorescence lines, Aromatic Infrared Bands (AIBs including aromatic CH, aliphatic CH, and their CD counterparts), CO2 ice, pure rotational and ro-vibrational lines from H2, and ro-vibrational lines HD, CO, and CH+, most of them detected for the first time towards a PDR. Their spatial distribution resolves the H and He ionisation structure in the Huygens region, gives insight into the geometry of the Bar, and confirms the large-scale stratification of PDRs. We observe numerous smaller scale structures whose typical size decreases with distance from Ori C and IR lines from CI, if solely arising from radiative recombination and cascade, reveal very high gas temperatures consistent with the hot irradiated surface of small-scale dense clumps deep inside the PDR. The H2 lines reveal multiple, prominent filaments which exhibit different characteristics. This leaves the impression of a "terraced" transition from the predominantly atomic surface region to the CO-rich molecular zone deeper in. This study showcases the discovery space created by JWST to further our understanding of the impact radiation from young stars has on their natal molecular cloud and proto-planetary disk, which touches on star- and planet formation as well as galaxy evolution.

52 pages, 30 figures, submitted to A&A

References in corpus (49)

• The James Webb Space Telescope
• The distance to the Orion Nebula
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope I. Overview of the instrument and its capabilities
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope III. Integral-field spectroscopy
• One Relation for All Wavelengths: The Far-Ultraviolet to Mid-Infrared Milky Way Spectroscopic R(V) Dependent Dust Extinction Relationship
• Photodissociation and X-Ray Dominated Regions
• Clustered and Triggered Star Formation in W5: Observations with Spitzer
• Compression and ablation of the photo-irradiated cloud the Orion Bar
• Million-Degree Plasma Pervading the Extended Orion Nebula
• The chemistry and spatial distribution of small hydrocarbons in UV-irradiated molecular clouds: the Orion Bar PDR
• The full infrared spectrum of molecular hydrogen
• 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
• The PAH emission characteristics of the reflection nebula NGC2023
• Formation of the Methyl Cation by Photochemistry in a Protoplanetary Disk
• PDRs4All: A JWST Early Release Science Program on radiative feedback from massive stars
• Mixed aliphatic and aromatic composition of evaporating very small grains in NGC 7023 revealed by the 3.4/3.3 $\mu$m ratio
• Expanding bubbles in Orion A: [CII] observations of M42, M43, and NGC 1977
• All the PAHs: an AKARI-Spitzer Cross Archival Spectroscopic Survey of Aromatic Emission in Galaxies
• Complex organic molecules in strongly UV-irradiated gas
• OH mid-infrared emission as a diagnostic of H${}_2$O UV photodissociation. I. Model and application to the HH 211 shock
• The Orion HII Region and the Orion Bar in the Mid-Infrared
• Complexes of triggered star formation in supergiant shell of Holmberg II
• Star formation around the HII region Sh2-235
• Deviations from He I Case B Recombination Theory and Extinction Corrections in the Orion Nebula
• Rotationally Warm Molecular Hydrogen in the Orion Bar
• The PhotoDissociation Region Toolbox: Software and Models for Astrophysical Analysis
• Polycyclic Aromatic Hydrocarbon emission in Spitzer/IRS maps II: A direct link between band profiles and the radiation field strength
• PAH Spectroscopy from 1-5 $\mu$m
• A Near-infrared Survey of UV-excited Molecular Hydrogen in Photodissociation Regions
• Merged ionization/dissociation fronts in planetary nebulae
• Isentropic thermal instability in atomic surface layers of photodissociation regions
• Photolysis-induced scrambling of PAHs as a mechanism for deuterium storage
• Carbon radio recombination lines from gigahertz to megahertz frequencies towards Orion A
• High angular resolution near-IR view of the Orion Bar revealed by Keck/NIRC2
• Deciphering the 3-D Orion Nebula-I: Expanding Shells in the Huygens Region
• Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy II: HH204
• Direct estimation of electron density in the Orion Bar PDR from mm-wave carbon recombination lines
• Helium line emissivities for nebular astrophysics
• Deuterated Polycyclic Aromatic Hydrocarbons in the Interstellar Medium: The C--D Band Strengths of Mono-Deuterated Species
• OH mid-infrared emission as a diagnostic of H${}_2$O UV photodissociation. II. Application to interstellar PDRs
• The role of highly vibrationally excited H2 initiating the N chemistry: Quantum study and 3-sigma detection of NH emission in the Orion Bar PDR
• Observations and analysis of CH${}^{+}$ vibrational emissions from the young, carbon-rich planetary nebula NGC 7027: a textbook example of chemical pumping
• Raman mapping of photodissociation regions
• Deuterated Polycyclic Aromatic Hydrocarbons in the Interstellar Medium: The C--D Band Strengths of Multi-Deuterated Species
• Illuminating the Tadpole's metamorphosis I: MUSE observations of a small globule in a sea of ionizing photons
• Near-infrared spectroscopy of a massive young stellar object in the direction toward the Galactic Center: XCN and aromatic C-D features
• Nano-grain depletion in photon-dominated regions
• Anomalous intensities in the infrared emission of CH${}^{+}$ explained by quantum nuclear motion and electric dipole calculations
• Tying Spitzer's IRS Calibration to IRAC: Observations of IRS Standard Stars

Cited by in corpus (33)

• The Galaxy Activity, Torus, and Outflow Survey (GATOS). V: Unveiling PAH survival and resilience in the circumnuclear regions of AGN with JWST
• PDRs4All XI. Detection of infrared CH${}^{+}$ and CH${}_3^{+}$ rovibrational emission in the Orion Bar and disk d203-506: evidence of chemical pumping
• PDRs4All VI: Probing the Photochemical Evolution of PAHs in the Orion Bar Using Machine Learning Techniques
• PDRs4All. X. ALMA and JWST detection of neutral carbon in the externally irradiated disk d203-506: Undepleted gas-phase carbon
• PDRs4All. XII. FUV-driven formation of hydrocarbon radicals and their relation with PAHs
• PDRs4All VII. The 3.3 $\mu$m aromatic infrared band as a tracer of physical properties of the ISM in galaxies
• JOYS: The [D/H] abundance derived from protostellar outflows across the Galactic disk measured with JWST
• JWST observations of the Horsehead photon-dominated region I. First results from multi-band near- and mid-infrared imaging
• PDRs4All XVI. Tracing aromatic infrared band characteristics in photodissociation region spectra with PAHFIT in the JWST era
• A tell-tale tracer for externally irradiated protoplanetary disks: comparing the [CI] 8727 A line and ALMA observations in proplyds
• PDRs4All XIII. Empirical prescriptions for the interpretation of JWST imaging observations of star-forming regions
• PDRs4All. V. Modelling the dust evolution across the illuminated edge of the Orion Bar
• Multiline observations of hydrogen, helium, and carbon radio-recombination lines toward Orion A: A detailed dynamical study and direct determination of physical conditions
• Detection of Deuterated Hydrocarbon Nanoparticles in the Whirlpool Galaxy, M51
• PDRs4All XV: CH radical and H${}_3^{+}$ molecular ion in the irradiated protoplanetary disk d203-506
• PDRs4All: XVIII. The evolution of the PAH ionisation and PAH size distribution across the Orion Bar
• NeuralPDR: Neural Differential Equations as surrogate models for Photodissociation Regions
• JWST observations of the Ring Nebula (NGC 6720) -- II. PAH emission
• Long-Lived Isomers of C${}_{11}$H${}_9^{+}$: New Experimental Insights from the PIRENEA Setup
• Aromatic Species in the Molecular Universe
• Weak, extended water vapor emission in the Horsehead nebula
• JWST Observations of Starbursts: Dust Processing in the M82 Superwind
• PDRs4All XVII: Formation and excitation of HD in photodissociation regions. Application to the Orion Bar
• SOFIA/upGREAT far-infrared spectroscopy of bright rimmed pillars in IC 1848
• Formation of methane and cyclohexane through the hydrogenation of toluene
• PDRs4All XIX. The 6 to 9 $\mu$m region as a probe of PAH charge and size in the Orion Bar
• JWST observations of photodissociation regions III. Dust modelling at the illuminated edge of the Horsehead PDR
• Mapping Interstellar Ice Inventory toward Class 0 Protostars in Star-forming Region Orion A with JWST Data
• PDRs4All XVIII. JWST-NIRCam Photometric properties of protoplanetary disks in the Orion Nebula Cluster
• Spatial distribution of organics in the Horsehead nebula: Signposts of chemistry driven by atomic carbon
• JWST observations of photodissociation regions. IV. Carbonaceous emission band sub-components in NGC 7023 have distinct spatial distributions
• Acenaphthene Derivatives as Signatures of C${}_{11}$H${}_9^{+}$ Reactivity with Methylated Naphthalenes
• Observations of Carbon Radio Recombination Lines with the NenuFAR telescope. I. Cassiopeia A and Cygnus A