Characterizing the PAH emission in the Orion Bar
| العنوان: | Characterizing the PAH emission in the Orion Bar |
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| المؤلفون: | C. Knight, Els Peeters, William D. Vacca, Alexander G. G. M. Tielens |
| المصدر: | Monthly Notices of the Royal Astronomical Society, 509(3), 3523-3546 |
| بيانات النشر: | Oxford University Press (OUP), 2021. |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | individual objects, Orion Bar, 010504 meteorology & atmospheric sciences, Infrared, photodissociation region (PDR), FOS: Physical sciences, chemistry.chemical_element, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Photodissociation region, spectroscopic, 01 natural sciences, Spectral line, Neon, Spitzer Space Telescope, Ionization, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ISM, 0105 earth and related environmental sciences, Physics, astrochemistry, Stratospheric Observatory for Infrared Astronomy, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, chemistry, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), infrared, techniques, Bar (unit) |
| الوصف: | We present 5--14~$\mu$m spectra at two different positions across the Orion Bar photodissociation region (PDR) obtained with the Infrared Spectrograph onboard the Spitzer Space Telescope and 3.3~$\mu$m PAH observations obtained with the Stratospheric Observatory for Infrared Astronomy (SOFIA). We aim to characterize emission from Polycyclic Aromatic Hydrocarbon (PAH), dust, atomic and molecular hydrogen, argon, sulfur, and neon as a function of distance from the primary illuminating source. We find that all the major PAH bands peak between the ionization front and the PDR front, as traced by H$_{2}$, while variations between these bands become more pronounced moving away from this peak into the face-on PDRs behind the PDR front and at the backside of the \HII\, region. While the relative PAH intensities are consistent with established PAH characteristics, we report unusual behaviours and attribute these to the PDR viewing angle and the strength of the FUV radiation field impinging on the PDRs. We determine the average PAH size which varies across the Orion Bar. We discuss subtle differences seen between the cationic PAH bands and highlight the photo-chemical evolution of carbonaceous species in this PDR environment. We find that PAHs are a good tracer of environmental properties such as the strength of the FUV radiation field and the PAH ionization parameter. Comment: 25 pages, 19 Figures. To be published in MNRAS |
| وصف الملف: | application/pdf |
| تدمد: | 1365-2966 0035-8711 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5fee816fee4a189a8dc0b1bfea64c8caTest https://doi.org/10.1093/mnras/stab3047Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....5fee816fee4a189a8dc0b1bfea64c8ca |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 13652966 00358711 |
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