FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX
Class I methanol masers are believed to be produced in the shock-excited environment around star-forming regions. Many authors have argued that the appearance of various subsets of class I masers may be indicative of specific evolutionary stages of star formation or excitation conditions. Until rece...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | en_US |
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Institute of Physics/American Astronomical Society
2015
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| Online Access: | http://hdl.handle.net/1721.1/95872 |
| _version_ | 1826192491232100352 |
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| author | Fish, Vincent L. Muehlbrad, Talitha C. Pratap, Preethi Sjouwerman, Loránt O. Strelnitski, Vladimir Pihlström, Ylva M. Bourke, Tyler L. |
| author2 | Haystack Observatory |
| author_facet | Haystack Observatory Fish, Vincent L. Muehlbrad, Talitha C. Pratap, Preethi Sjouwerman, Loránt O. Strelnitski, Vladimir Pihlström, Ylva M. Bourke, Tyler L. |
| author_sort | Fish, Vincent L. |
| collection | MIT |
| description | Class I methanol masers are believed to be produced in the shock-excited environment around star-forming regions. Many authors have argued that the appearance of various subsets of class I masers may be indicative of specific evolutionary stages of star formation or excitation conditions. Until recently, however, no major interferometer was capable of imaging the important 36 GHz transition. We report on Expanded Very Large Array observations of the 36 GHz methanol masers and Submillimeter Array observations of the 229 GHz methanol masers in DR21(OH), DR21N, and DR21W. The distribution of 36 GHz masers in the outflow of DR21(OH) is similar to that of the other class I methanol transitions, with numerous multitransition spatial overlaps. At the site of the main continuum source in DR21(OH), class I masers at 36 and 229 GHz are found in virtual overlap with class II 6.7 GHz masers. To the south of the outflow, the 36 GHz masers are scattered over a large region but usually do not appear coincident with 44 GHz masers. In DR21W, we detect an "S-curve" signature in Stokes V that implies a large value of the magnetic field strength if interpreted as due to Zeeman splitting, suggesting either that class I masers may exist at higher densities than previously believed or that the direct Zeeman interpretation of S-curve Stokes V profiles in class I masers may be incorrect. We find a diverse variety of different maser phenomena in these sources, suggestive of differing physical conditions among them. |
| first_indexed | 2024-09-23T09:16:40Z |
| format | Article |
| id | mit-1721.1/95872 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T09:16:40Z |
| publishDate | 2015 |
| publisher | Institute of Physics/American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/958722022-09-30T14:08:00Z FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX Fish, Vincent L. Muehlbrad, Talitha C. Pratap, Preethi Sjouwerman, Loránt O. Strelnitski, Vladimir Pihlström, Ylva M. Bourke, Tyler L. Haystack Observatory Fish, Vincent L. Pratap, Preethi Class I methanol masers are believed to be produced in the shock-excited environment around star-forming regions. Many authors have argued that the appearance of various subsets of class I masers may be indicative of specific evolutionary stages of star formation or excitation conditions. Until recently, however, no major interferometer was capable of imaging the important 36 GHz transition. We report on Expanded Very Large Array observations of the 36 GHz methanol masers and Submillimeter Array observations of the 229 GHz methanol masers in DR21(OH), DR21N, and DR21W. The distribution of 36 GHz masers in the outflow of DR21(OH) is similar to that of the other class I methanol transitions, with numerous multitransition spatial overlaps. At the site of the main continuum source in DR21(OH), class I masers at 36 and 229 GHz are found in virtual overlap with class II 6.7 GHz masers. To the south of the outflow, the 36 GHz masers are scattered over a large region but usually do not appear coincident with 44 GHz masers. In DR21W, we detect an "S-curve" signature in Stokes V that implies a large value of the magnetic field strength if interpreted as due to Zeeman splitting, suggesting either that class I masers may exist at higher densities than previously believed or that the direct Zeeman interpretation of S-curve Stokes V profiles in class I masers may be incorrect. We find a diverse variety of different maser phenomena in these sources, suggestive of differing physical conditions among them. National Science Foundation (U.S.) (Experiences for Undergraduates program) Smithsonian Institution Academia Sinica (Beijing, China) 2015-03-05T16:00:34Z 2015-03-05T16:00:34Z 2011-03 2010-09 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/95872 Fish, Vincent L., Talitha C. Muehlbrad, Preethi Pratap, Loránt O. Sjouwerman, Vladimir Strelnitski, Ylva M. Pihlström, and Tyler L. Bourke. “FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX.” The Astrophysical Journal 729, no. 1 (February 4, 2011): 14. © 2011 American Astronomical Society. en_US http://dx.doi.org/10.1088/0004-637x/729/1/14 Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Institute of Physics/American Astronomical Society American Astronomical Society |
| spellingShingle | Fish, Vincent L. Muehlbrad, Talitha C. Pratap, Preethi Sjouwerman, Loránt O. Strelnitski, Vladimir Pihlström, Ylva M. Bourke, Tyler L. FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX |
| title | FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX |
| title_full | FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX |
| title_fullStr | FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX |
| title_full_unstemmed | FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX |
| title_short | FIRST INTERFEROMETRIC IMAGES OF THE 36 GHz METHANOL MASERS IN THE DR21 COMPLEX |
| title_sort | first interferometric images of the 36 ghz methanol masers in the dr21 complex |
| url | http://hdl.handle.net/1721.1/95872 |
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