A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter Array
Massive star-forming regions exhibit a rich chemistry with complex gas distributions, especially on small scales. While surveys have yielded constraints on typical gas conditions, they often have coarse spatial resolution and limited bandwidths. Thus, to establish an interpretative framework for the...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Supplement Series |
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| Online Access: | https://doi.org/10.3847/1538-4365/ad9477 |
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| author | Charles J. Law Qizhou Zhang Arielle C. Frommer Karin I. Öberg Roberto Galván-Madrid Eric Keto Hauyu Baobab Liu Paul T. P. Ho Andrés F. Izquierdo L. Ilsedore Cleeves |
| author_facet | Charles J. Law Qizhou Zhang Arielle C. Frommer Karin I. Öberg Roberto Galván-Madrid Eric Keto Hauyu Baobab Liu Paul T. P. Ho Andrés F. Izquierdo L. Ilsedore Cleeves |
| author_sort | Charles J. Law |
| collection | DOAJ |
| description | Massive star-forming regions exhibit a rich chemistry with complex gas distributions, especially on small scales. While surveys have yielded constraints on typical gas conditions, they often have coarse spatial resolution and limited bandwidths. Thus, to establish an interpretative framework for these efforts, detailed observations that simultaneously provide high sensitivity, spatial resolution, and large bandwidths for a subset of diverse sources are needed. Here, we present wide-band (≈32 GHz) Submillimeter Array (SMA) observations of four high-mass star-forming regions (G28.20-0.05, G20.08-0.14 N, G35.58-0.03, and W33 Main) at subarcsecond resolution, where we detect and spatially resolve hundreds of lines from over 60 molecules, including many complex organic molecules (COMs). The chemical richness of our sample is consistent with an evolutionary sequence from the line-rich hot cores and hypercompact H ii regions of G28.20-0.05 and G20.08-0.14 N to the more chemically modest ultracompact H ii regions in G35.58-0.03, followed by the molecule-poor H ii region W33 Main. We detect lines across a range of excitation conditions ( E _u ≈ 20 to ≳800 K) and from numerous isotopologues, which enables robust estimates of gas properties. We derive nearly constant COM column density ratios that agree with literature values in other low- and high-mass protostellar cores, supporting the idea that COM abundances are set during the pre-stellar phase. In all regions, we identify spatial offsets among different molecular families, due to a combination of source physical structure and chemistry. In particular, we find potential evidence of carbon grain sublimation in G28.20-0.05 and identify an elemental oxygen gradient and rich sulfur chemistry in G35.58-0.03. Overall, these results demonstrate that the SMA's wide bandwidth is a powerful tool to untangle the complex molecular gas structures associated with massive star formation. |
| format | Article |
| id | doaj-art-728ddef582414f7788bac80fc5e63b5e |
| institution | Kabale University |
| issn | 0067-0049 |
| language | English |
| publishDate | 2025-01-01 |
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| series | The Astrophysical Journal Supplement Series |
| spelling | doaj-art-728ddef582414f7788bac80fc5e63b5e2025-01-20T13:52:40ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-0127625410.3847/1538-4365/ad9477A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter ArrayCharles J. Law0https://orcid.org/0000-0003-1413-1776Qizhou Zhang1https://orcid.org/0000-0003-2384-6589Arielle C. Frommer2https://orcid.org/0009-0005-9407-9278Karin I. Öberg3https://orcid.org/0000-0001-8798-1347Roberto Galván-Madrid4https://orcid.org/0000-0003-1480-4643Eric Keto5Hauyu Baobab Liu6https://orcid.org/0000-0003-2300-2626Paul T. P. Ho7https://orcid.org/0000-0002-3412-4306Andrés F. Izquierdo8https://orcid.org/0000-0001-8446-3026L. Ilsedore Cleeves9https://orcid.org/0000-0003-2076-8001Department of Astronomy, University of Virginia , Charlottesville, VA 22904, USA ; cjl8rd@virginia.eduCenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden St., Cambridge, MA 02138, USACenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden St., Cambridge, MA 02138, USACenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden St., Cambridge, MA 02138, USAInstituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México , Morelia, Michoacán 58089, MéxicoCenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden St., Cambridge, MA 02138, USADepartment of Physics, National Sun Yat-Sen University , No. 70, Lien-Hai Rd., Kaohsiung City 80424, Taiwan, ROC; Center of Astronomy and Gravitation, National Taiwan Normal University , Taipei 116, TaiwanInstitute of Astronomy and Astrophysics , Academia Sinica, 11F of Astronomy–Mathematics Building, AS/NTU No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan, ROCEuropean Southern Observatory , Karl-Schwarzschild-Straße 2, 85748 Garching bei München, Germany; Leiden Observatory, Leiden University , 2300 RA Leiden, The Netherlands; Department of Astronomy, University of Florida , Gainesville, FL 32611, USADepartment of Astronomy, University of Virginia , Charlottesville, VA 22904, USA ; cjl8rd@virginia.eduMassive star-forming regions exhibit a rich chemistry with complex gas distributions, especially on small scales. While surveys have yielded constraints on typical gas conditions, they often have coarse spatial resolution and limited bandwidths. Thus, to establish an interpretative framework for these efforts, detailed observations that simultaneously provide high sensitivity, spatial resolution, and large bandwidths for a subset of diverse sources are needed. Here, we present wide-band (≈32 GHz) Submillimeter Array (SMA) observations of four high-mass star-forming regions (G28.20-0.05, G20.08-0.14 N, G35.58-0.03, and W33 Main) at subarcsecond resolution, where we detect and spatially resolve hundreds of lines from over 60 molecules, including many complex organic molecules (COMs). The chemical richness of our sample is consistent with an evolutionary sequence from the line-rich hot cores and hypercompact H ii regions of G28.20-0.05 and G20.08-0.14 N to the more chemically modest ultracompact H ii regions in G35.58-0.03, followed by the molecule-poor H ii region W33 Main. We detect lines across a range of excitation conditions ( E _u ≈ 20 to ≳800 K) and from numerous isotopologues, which enables robust estimates of gas properties. We derive nearly constant COM column density ratios that agree with literature values in other low- and high-mass protostellar cores, supporting the idea that COM abundances are set during the pre-stellar phase. In all regions, we identify spatial offsets among different molecular families, due to a combination of source physical structure and chemistry. In particular, we find potential evidence of carbon grain sublimation in G28.20-0.05 and identify an elemental oxygen gradient and rich sulfur chemistry in G35.58-0.03. Overall, these results demonstrate that the SMA's wide bandwidth is a powerful tool to untangle the complex molecular gas structures associated with massive star formation.https://doi.org/10.3847/1538-4365/ad9477Young stellar objectsStar forming regionsInterstellar moleculesHigh angular resolutionComplex organic molecules |
| spellingShingle | Charles J. Law Qizhou Zhang Arielle C. Frommer Karin I. Öberg Roberto Galván-Madrid Eric Keto Hauyu Baobab Liu Paul T. P. Ho Andrés F. Izquierdo L. Ilsedore Cleeves A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter Array The Astrophysical Journal Supplement Series Young stellar objects Star forming regions Interstellar molecules High angular resolution Complex organic molecules |
| title | A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter Array |
| title_full | A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter Array |
| title_fullStr | A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter Array |
| title_full_unstemmed | A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter Array |
| title_short | A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter Array |
| title_sort | wideband chemical survey of massive star forming regions at subarcsecond resolution with the submillimeter array |
| topic | Young stellar objects Star forming regions Interstellar molecules High angular resolution Complex organic molecules |
| url | https://doi.org/10.3847/1538-4365/ad9477 |
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