Backscattering and Line Broadening in Orion
Examination of emission lines in high-velocity-resolution optical spectra of the Orion Nebula confirms that the velocity component on the red wing of the main ionization front emission line is due to backscattering in the Photon Dominated Region. This scattered light component has a weak wavelength...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2022-01-01
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| Series: | The Astronomical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-3881/ac9f44 |
| _version_ | 1797702097956765696 |
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| author | C. R. O’Dell G. J. Ferland J. E. Méndez-Delgado |
| author_facet | C. R. O’Dell G. J. Ferland J. E. Méndez-Delgado |
| author_sort | C. R. O’Dell |
| collection | DOAJ |
| description | Examination of emission lines in high-velocity-resolution optical spectra of the Orion Nebula confirms that the velocity component on the red wing of the main ionization front emission line is due to backscattering in the Photon Dominated Region. This scattered light component has a weak wavelength dependence that is consistent with either general interstellar medium particles or particles in the foreground of the Orion Nebula Cluster. An anomalous line-broadening component that has been known for 60+ years is characterized in unprecedented detail. Although this extra broadening may be due to turbulence along the line of sight of our spectra, we explore the possibility that it is due to Alfvén waves in conditions where the ratio of magnetic and thermal energies are about equal and constant throughout the ionized gas. |
| first_indexed | 2024-03-12T04:45:15Z |
| format | Article |
| id | doaj.art-a74d5c0bf22a4d769ebf830c2ae8c83d |
| institution | Directory Open Access Journal |
| issn | 1538-3881 |
| language | English |
| last_indexed | 2024-03-12T04:45:15Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj.art-a74d5c0bf22a4d769ebf830c2ae8c83d2023-09-03T09:29:30ZengIOP PublishingThe Astronomical Journal1538-38812022-01-0116512110.3847/1538-3881/ac9f44Backscattering and Line Broadening in OrionC. R. O’Dell0https://orcid.org/0000-0003-3323-2310G. J. Ferland1https://orcid.org/0000-0003-4503-6333J. E. Méndez-Delgado2https://orcid.org/0000-0002-6972-6411Department of Physics and Astronomy, Vanderbilt University , Nashville, TN 37235-1807, USADepartment of Physics and Astronomy, University of Kentucky , Lexington, KY 40506, USAAstronomisches Rechen-Institut, Zentrum für Astronomie der Universitat Heidelberg , Mönchhofstraße 12-14, D-69120 Heidelberg, Germany; Instituto de Astrofísica de Canarias (IAC) , E-38205 La Laguna, Spain; Departamento de Astrofísica, Universidad de La Laguna , E-38206 La Laguna, SpainExamination of emission lines in high-velocity-resolution optical spectra of the Orion Nebula confirms that the velocity component on the red wing of the main ionization front emission line is due to backscattering in the Photon Dominated Region. This scattered light component has a weak wavelength dependence that is consistent with either general interstellar medium particles or particles in the foreground of the Orion Nebula Cluster. An anomalous line-broadening component that has been known for 60+ years is characterized in unprecedented detail. Although this extra broadening may be due to turbulence along the line of sight of our spectra, we explore the possibility that it is due to Alfvén waves in conditions where the ratio of magnetic and thermal energies are about equal and constant throughout the ionized gas.https://doi.org/10.3847/1538-3881/ac9f44Emission nebulaeH II regions |
| spellingShingle | C. R. O’Dell G. J. Ferland J. E. Méndez-Delgado Backscattering and Line Broadening in Orion The Astronomical Journal Emission nebulae H II regions |
| title | Backscattering and Line Broadening in Orion |
| title_full | Backscattering and Line Broadening in Orion |
| title_fullStr | Backscattering and Line Broadening in Orion |
| title_full_unstemmed | Backscattering and Line Broadening in Orion |
| title_short | Backscattering and Line Broadening in Orion |
| title_sort | backscattering and line broadening in orion |
| topic | Emission nebulae H II regions |
| url | https://doi.org/10.3847/1538-3881/ac9f44 |
| work_keys_str_mv | AT crodell backscatteringandlinebroadeninginorion AT gjferland backscatteringandlinebroadeninginorion AT jemendezdelgado backscatteringandlinebroadeninginorion |