PDRs4All IV. An embarrassment of riches: Aromatic infrared bands in the Orion Bar
文献类型：期刊论文
| 作者 | Chown, Ryan96,97; Sidhu, Ameek96,97; Peeters, Els95,96,97; Tielens, Alexander G. G. M.93,94; Cami, Jan95,96,97; Berné, Olivier92; Habart, Emilie91; Alarcón, Felipe90; Canin, Amélie92; Schroetter, Ilane92 |
| 刊名 | ASTRONOMY & ASTROPHYSICS
 |
| 出版日期 | 2024-05-14 |
| 卷号 | 685 |
| 关键词 | astrochemistry infrared: ISM ISM: molecules ISM: individual objects: Orion Bar photon-dominated region (PDR) techniques: spectroscopic |
| ISSN号 | 0004-6361 |
| DOI | 10.1051/0004-6361/202346662 |
| 产权排序 | 第55完成单位 |
| 文献子类 | Article |
| 英文摘要 | Context. Mid-infrared observations of photodissociation regions (PDRs) are dominated by strong emission features called aromatic infrared bands (AIBs). The most prominent AIBs are found at 3.3, 6.2, 7.7, 8.6, and 11.2 mu m. The most sensitive, highest-resolution infrared spectral imaging data ever taken of the prototypical PDR, the Orion Bar, have been captured by JWST. These high-quality data allow for an unprecedentedly detailed view of AIBs. Aims. We provide an inventory of the AIBs found in the Orion Bar, along with mid-IR template spectra from five distinct regions in the Bar: the molecular PDR (i.e. the three H-2 dissociation fronts), the atomic PDR, and the H II region. Methods. We used JWST NIRSpec IFU and MIRI MRS observations of the Orion Bar from the JWST Early Release Science Program, PDRs4All (ID: 1288). We extracted five template spectra to represent the morphology and environment of the Orion Bar PDR. We investigated and characterised the AIBs in these template spectra. We describe the variations among them here. Results. The superb sensitivity and the spectral and spatial resolution of these JWST observations reveal many details of the AIB emission and enable an improved characterization of their detailed profile shapes and sub-components. The Orion Bar spectra are dominated by the well-known AIBs at 3.3, 6.2, 7.7, 8.6, 11.2, and 12.7 mu m with well-defined profiles. In addition, the spectra display a wealth of weaker features and sub-components. The widths of many AIBs show clear and systematic variations, being narrowest in the atomic PDR template, but showing a clear broadening in the H II region template while the broadest bands are found in the three dissociation front templates. In addition, the relative strengths of AIB (sub-)components vary among the template spectra as well. All AIB profiles are characteristic of class A sources as designated by Peeters (2022, A&A, 390, 1089), except for the 11.2 mu m AIB profile deep in the molecular zone, which belongs to class B-11.2. Furthermore, the observations show that the sub-components that contribute to the 5.75, 7.7, and 11.2 mu m AIBs become much weaker in the PDR surface layers. We attribute this to the presence of small, more labile carriers in the deeper PDR layers that are photolysed away in the harsh radiation field near the surface. The 3.3/11.2 AIB intensity ratio decreases by about 40% between the dissociation fronts and the H II region, indicating a shift in the polycyclic aromatic hydrocarbon (PAH) size distribution to larger PAHs in the PDR surface layers, also likely due to the effects of photochemistry. The observed broadening of the bands in the molecular PDR is consistent with an enhanced importance of smaller PAHs since smaller PAHs attain a higher internal excitation energy at a fixed photon energy. Conclusions. Spectral-imaging observations of the Orion Bar using JWST yield key insights into the photochemical evolution of PAHs, such as the evolution responsible for the shift of 11.2 mu m AIB emission from class B-11.2 in the molecular PDR to class A(11.2) in the PDR surface layers. This photochemical evolution is driven by the increased importance of FUV processing in the PDR surface layers, resulting in a weeding out of the weakest links of the PAH family in these layers. For now, these JWST observations are consistent with a model in which the underlying PAH family is composed of a few species: the so-called 'grandPAHs'. |
| 学科主题 | 天文学 |
| URL标识 | 查看原文 |
| 出版地 | 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE |
| WOS关键词 | WEBB-SPACE-TELESCOPE ; INTERSTELLAR-EMISSION FEATURE ; IR ABSORPTION-SPECTROSCOPY ; PHOTON-DOMINATED REGION ; LARGE-MAGELLANIC-CLOUD ; MU-M EMISSION ; PAH EMISSION ; HYDROCARBON EMISSION ; REFLECTION NEBULA ; PHOTODISSOCIATION REGIONS |
| 资助项目 | Association of Universities for Research in Astronomy, Inc., under NASA[NAS 5-03127]; NASA Space Telescope Science Institute[1288]; University of Western Ontario; Institute for Earth and Space Exploration; Canadian Space Agency (CSA)[22JWGO1-16]; Natural Sciences and Engineering Research Council of Canada; Dutch Science Agency; NWO; NASA Ames Research Center through the San Jose State University Research Foundation[80NSSC22M0107]; Programme National Physique et Chimie du Milieu Interstellaire (PCMI) of CNRS/INSU with INC/INP; CEA; CNES; Spanish MCINN[PID2019-106110GB-I00]; JSPS Bilateral Program[120219939]; Deutsche Forschungsgemeinschaft (DFG)[184018867]; Spanish program Unidad de Excelencia Maria de Maeztu - MCIN/AEI[CEX2020-001058-M]; United Arab Emirates University (UAEU) through UAEU Program for Advanced Research (UPAR)[G00003479]; Department of Science and Technology -SERB via Core Research Grant (DST-CRG)[SERB-CRG/2021/000907]; Institutes of Eminence (IoE) incentive grant; BHU[incentive/2021-22/32439]; Banaras Hindu University, Varanasi; CAS; NASA; DST; Swedish Research Council[2020-03437]; MCIN/AEI[EUR2021-122006]; MCIN/AEI[TED2021-129416A-I00]; MCIN/AEI[PID2021-125309OA-I00]; European Union NextGenerationEU/PRTR; RSCF[21-12-00373] |
| WOS研究方向 | Astronomy & Astrophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001271220100003 |
| 出版者 | EDP SCIENCES S A |
| 资助机构 | Association of Universities for Research in Astronomy, Inc., under NASA[NAS 5-03127] ; NASA Space Telescope Science Institute[1288] ; University of Western Ontario ; Institute for Earth and Space Exploration ; Canadian Space Agency (CSA)[22JWGO1-16] ; Natural Sciences and Engineering Research Council of Canada ; Dutch Science Agency ; NWO ; NASA Ames Research Center through the San Jose State University Research Foundation[80NSSC22M0107] ; Programme National Physique et Chimie du Milieu Interstellaire (PCMI) of CNRS/INSU with INC/INP ; CEA ; CNES ; Spanish MCINN[PID2019-106110GB-I00] ; JSPS Bilateral Program[120219939] ; Deutsche Forschungsgemeinschaft (DFG)[184018867] ; Spanish program Unidad de Excelencia Maria de Maeztu - MCIN/AEI[CEX2020-001058-M] ; United Arab Emirates University (UAEU) through UAEU Program for Advanced Research (UPAR)[G00003479] ; Department of Science and Technology -SERB via Core Research Grant (DST-CRG)[SERB-CRG/2021/000907] ; Institutes of Eminence (IoE) incentive grant ; BHU[incentive/2021-22/32439] ; Banaras Hindu University, Varanasi ; CAS ; NASA ; DST ; Swedish Research Council[2020-03437] ; MCIN/AEI[EUR2021-122006, TED2021-129416A-I00, PID2021-125309OA-I00] ; European Union NextGenerationEU/PRTR ; RSCF[21-12-00373] |
| 版本 | 出版稿 |
| 源URL | [http://ir.ynao.ac.cn/handle/114a53/27641]  |
| 专题 | 云南天文台_其他 |
| 作者单位 | 1.Institute of Deep Space Sciences, Deep Space Exploration Laboratory, Hefei 230026, PR China 2.Star and Planet Formation Laboratory, RIKEN Cluster for Pioneering Research, Hirosawa 2-1, Wako, Saitama 351-0198, Japan; 3.School of Physics and Astronomy, Sun Yat-sen University, 2 Da Xue Road, Tangjia, Zhuhai 519000, Guangdong Province, PR China; 4.Department of Physics, Texas State University, San Marcos, TX 78666, USA; 5.Department of Physics, Stockholm University, 10691 Stockholm, Sweden; 6.Space Science Institute, 4765 Walnut St., R203, Boulder, CO 80301, USA; 7.Astronomy Department, Ohio State University, Columbus, OH 43210, USA; 8.School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, UK; 9.Center for Astrophysics and Space Sciences, Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; 10.Instituto de Matemática, Estatística e Física, Universidade Federal do Rio Grande, 96201-900 Rio Grande, RS, Brazil; |
| 推荐引用方式 GB/T 7714 | Chown, Ryan,Sidhu, Ameek,Peeters, Els,et al. PDRs4All IV. An embarrassment of riches: Aromatic infrared bands in the Orion Bar[J]. ASTRONOMY & ASTROPHYSICS,2024,685. |
| APA | Chown, Ryan.,Sidhu, Ameek.,Peeters, Els.,Tielens, Alexander G. G. M..,Cami, Jan.,...&Zhen, Junfeng.(2024).PDRs4All IV. An embarrassment of riches: Aromatic infrared bands in the Orion Bar.ASTRONOMY & ASTROPHYSICS,685. |
| MLA | Chown, Ryan,et al."PDRs4All IV. An embarrassment of riches: Aromatic infrared bands in the Orion Bar".ASTRONOMY & ASTROPHYSICS 685(2024). |
入库方式： OAI收割
来源：云南天文台
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