PDRs4All. II. JWST's NIR and MIR imaging view of the Orion Nebula

E. Habart (1) , E. Peeters (2) , O. Berné (3) , B. Trahin (4, 1) , A. Canin (3) , R. Chown , A. Sidhu , D. van de Putte (5) , F. Alarcon , I. Schroetter (3) , E. Dartois (6) , S. Vicente , A. Abergel (1) , E. Bergin (7) , J. Bernard-Salas (1) , C. Boersma (8) , E. Bron (9) , J. Cami (10) , S. Cuadrado , D. Dicken (11, 1) , Meriem Elyajouri, (1) , Asunción Fuente, , R. Goicoechea, Javier , D. Gordon, Karl , Lina Issa, , Christine Joblin, (3) , Olga Kannavou, (1) , Baria Khan, , Ozan Lacinbala, , David Languignon, , Romane Le Gal, (12, 13) , Alexandros Maragkoudakis, , Raphael Meshaka, (1, 10) , Yoko Okada, , Takashi Onaka, , Sofia Pasquini, , W. Pound, Marc , Massimo Robberto, , Markus Röllig, , Bethany Schefter, , Thiébaut Schirmer, (1) , Benoit Tabone, (1) , M. Tielens, Alexander G. G. , G. Wolfire, Mark , Marion Zannese, (1) , Nathalie Ysard, (1) , Marc-Antoine Miville-Deschenes, (14) , Isabel Aleman, , Louis Allamandola, , Rebecca Auchettl, , Antonio Baratta, Giuseppe , Salma Bejaoui, , P. Bera, Partha , H. Black, John , Francois Boulanger, , Jordy Bouwman, , Bernhard Brandl, , Philippe Brechignac, , Sandra Brünken, , Mridusmita Buragohain, , Rew Burkhardt, , Alessandra Candian, , Stéphanie Cazaux, , Jose Cernicharo, , Marin Chabot (15) , Shubhadip Chakraborty, , Jason Champion, , J. Colgan, Sean W. , R. Cooke, Ilsa , Audrey Coutens, (3) , J. Cox, Nick L. , Karine Demyk, (3) , Jennifer Donovan Meyer, , Sacha Foschino, , Pedro García-Lario, , Lisseth Gavilan, , Maryvonne Gerin, , A. Gottlieb, Carl , Pierre Guillard, (16) , Antoine Gusdorf (10) , Patrick Hartigan, , Jinhua He, , Eric Herbst, , Liv Hornekaer, , Cornelia Jäger, , Eduardo Janot-Pacheco, , Michael Kaufman, , Orcid Kemper, Francisca Search By , Sarah Kendrew, , S. Kirsanova, Maria , Pamela Klaassen, , Sun Kwok, , Orcid Labiano, Álvaro Search By , J. Lee, Timothy , Bertrand Lefloch, , Franck Le Petit, , Aigen Li, , Hendrik Linz, , J. Mackie, Cameron , C. Madden, Suzanne (14) , Joëlle Mascetti, , A. Mcguire, Brett , Pablo Merino, , R. Micelotta, Elisabetta , Karl Misselt, , A. Morse, Jon , Giacomo Mulas, , Naslim Neelamkodan, , Ryou Ohsawa, , Alain Omont, , Roberta Paladini, , Elisabetta Palumbo, Maria , Amit Pathak, , J. Pendleton, Yvonne , Annemieke Petrignani, , Thomas Pino, , Elena Puga, , Naseem Rangwala, , Mathias Rapacioli (17, 18) , Alessandra Ricca, , Julia Roman-Duval, , Joseph Roser, , Evelyne Roueff, , Gaël Rouillé, , Farid Salama, , A. Sales, Dinalva , Karin Sandstrom, , Peter Sarre, , Ella Sciamma-O'Brien, , Kris Sellgren, , S. Shenoy, Sachindev , David Teyssier, , D. Thomas, Richard , Aditya Togi, , Laurent Verstraete, (1) , N. Witt, Adolf , Alwyn Wootten, , Henning Zettergren, , E. Zhang, Ziwei , Junfeng Zhen,

1 IAS - Institut d'astrophysique spatiale
2 Haga Teaching Hospital [Hague]
3 IRAP - Institut de recherche en astrophysique et planétologie
4 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
5 Ghent University Hospital
6 ISMO - Institut des Sciences Moléculaires d'Orsay
7 Department of Astronomy [Ann Arbor]
8 ARC - NASA Ames Research Center
9 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
10 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres
11 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
12 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
13 IRAM - Institut de RadioAstronomie Millimétrique
14 CEA - CEA- Saclay
15 IJCLab - Laboratoire de Physique des 2 Infinis Irène Joliot-Curie
16 IAP - Institut d'Astrophysique de Paris
17 LCPQ - Laboratoire de Chimie et Physique Quantiques
18 MAD - Modélisation, Agrégats, Dynamique (LCPQ)

Context. The James Webb Space Telescope (JWST) has captured the most detailed and sharpest infrared (IR) images ever taken of the inner region of the Orion Nebula, the nearest massive star formation region, and a prototypical highly irradiated dense photo-dissociation region (PDR).Aims. We investigate the fundamental interaction of far-ultraviolet (FUV) photons with molecular clouds. The transitions across the ionization front (IF), dissociation front (DF), and the molecular cloud are studied at high-angular resolution. These transitions are relevant to understanding the effects of radiative feedback from massive stars and the dominant physical and chemical processes that lead to the IR emission that JWST will detect in many Galactic and extragalactic environments.Methods. We utilized NIRCam and MIRI to obtain sub-arcsecond images over ~150″ and 42″ in key gas phase lines (e.g., Pa α, Br α, [FeII] 1.64 µm, H2 1−0 S(1) 2.12 µm, 0–0 S(9) 4.69 µm), aromatic and aliphatic infrared bands (aromatic infrared bands at 3.3–3.4 µm, 7.7, and 11.3 µm), dust emission, and scattered light. Their emission are powerful tracers of the IF and DF, FUV radiation field and density distribution. Using NIRSpec observations the fractional contributions of lines, AIBs, and continuum emission to our NIRCam images were estimated. A very good agreement is found for the distribution and intensity of lines and AIBs between the NIRCam and NIRSpec observations.Results. Due to the proximity of the Orion Nebula and the unprecedented angular resolution of JWST, these data reveal that the molecular cloud borders are hyper structured at small angular scales of ~0.1–1″ (~0.0002–0.002 pc or ~40–400 au at 414 pc). A diverse set of features are observed such as ridges, waves, globules and photoevaporated protoplanetary disks. At the PDR atomic to molecular transition, several bright features are detected that are associated with the highly irradiated surroundings of the dense molecular condensations and embedded young star. Toward the Orion Bar PDR, a highly sculpted interface is detected with sharp edges and density increases near the IF and DF. This was predicted by previous modeling studies, but the fronts were unresolved in most tracers. The spatial distribution of the AIBs reveals that the PDR edge is steep and is followed by an extensive warm atomic layer up to the DF with multiple ridges. A complex, structured, and folded H0/H2 DF surface was traced by the H2 lines. This dataset was used to revisit the commonly adopted 2D PDR structure of the Orion Bar as our observations show that a 3D “terraced” geometry is required to explain the JWST observations. JWST provides us with a complete view of the PDR, all the way from the PDR edge to the substructured dense region, and this allowed us to determine, in detail, where the emission of the atomic and molecular lines, aromatic bands, and dust originate.Conclusions. This study offers an unprecedented dataset to benchmark and transform PDR physico-chemical and dynamical models for the JWST era. A fundamental step forward in our understanding of the interaction of FUV photons with molecular clouds and the role of FUV irradiation along the star formation sequence is provided.

Keywords: infrared: ISM; photon-dominated region (PDR); ISM: clouds

Domains: Astrophysics [astro-ph]

E. Habart, E. Peeters, O. Berné, B. Trahin, A. Canin, et al.. PDRs4All. II. JWST's NIR and MIR imaging view of the Orion Nebula. Astronomy & Astrophysics - A&A, 2024, 685, pp.A73. ⟨10.1051/0004-6361/202346747⟩. ⟨hal-04239307⟩