Structure and Kinematics of Sh2-138—A Distant Hub-filament System in the Outer Galactic Plane
We present a molecular line study of the Sh2-138 (IRAS 22308+5812) hub-filament system with the aim of investigating its structure and kinematics. Archival CO molecular line data from the Canadian Galactic Plane Survey (CO( J = 1–0)) for the wider region (∼50′ × 50′) and the James Clerk Maxwell Tele...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acb8bc |
| _version_ | 1827827778348646400 |
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| author | Kshitiz K. Mallick Lokesh K. Dewangan Devendra K. Ojha Tapas Baug Igor I. Zinchenko |
| author_facet | Kshitiz K. Mallick Lokesh K. Dewangan Devendra K. Ojha Tapas Baug Igor I. Zinchenko |
| author_sort | Kshitiz K. Mallick |
| collection | DOAJ |
| description | We present a molecular line study of the Sh2-138 (IRAS 22308+5812) hub-filament system with the aim of investigating its structure and kinematics. Archival CO molecular line data from the Canadian Galactic Plane Survey (CO( J = 1–0)) for the wider region (∼50′ × 50′) and the James Clerk Maxwell Telescope (CO(3–2), ^13 CO(3–2), and C ^18 O(3–2)) for the central portion (∼5′ × 5′) have been utilized. Analysis of the CO(1–0) spectra for the extended region in conjunction with the identification of the hub and filament using a column density map and the getsf tool, respectively, reveals a complex structure with the spectral extraction for the central position displaying multiple velocity components. Based on the Herschel 70 μ m warm dust emission, one of the filaments in the extended region was inferred to be associated with active star formation, and is host to a Bolocam 1.1 mm clump of ∼1606 M _☉ . An integrated intensity map of ^13 CO(3–2) emission, constructed from clumps detected at above 5 σ in position–position–velocity space, reveals three filamentary structures (labeled the western filament (W-f), southwestern filament (SW-f), and southeast filament (SE-f)) in the central portion. Velocity gradients observed in ^13 CO(3–2) position–velocity slices point to longitudinal gas flow along the filaments into the central region. Filaments W-f, SW-f, and SE-f were calculated to have observed line masses of ∼32, 33.5, and 50 M _☉ pc ^−1 , respectively. The cloud was found to be dominated by supersonic and nonthermal motions, with high Mach numbers (≳3) and a low thermal-to-nonthermal pressure ratio (∼0.01–0.1). |
| first_indexed | 2024-03-12T03:37:25Z |
| format | Article |
| id | doaj.art-0c7278720a9d41d9b62966e61d73ab7b |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:37:25Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-0c7278720a9d41d9b62966e61d73ab7b2023-09-03T13:08:01ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01944222810.3847/1538-4357/acb8bcStructure and Kinematics of Sh2-138—A Distant Hub-filament System in the Outer Galactic PlaneKshitiz K. Mallick0https://orcid.org/0000-0002-3873-6449Lokesh K. Dewangan1https://orcid.org/0000-0001-6725-0483Devendra K. Ojha2https://orcid.org/0000-0001-9312-3816Tapas Baug3https://orcid.org/0000-0003-0295-6586Igor I. Zinchenko4https://orcid.org/0000-0003-2793-8229Aryabhatta Research Institute of Observational Sciences (ARIES) , Manora Peak, Nainital, 263002, India ; kshiitiz@gmail.comPhysical Research Laboratory , Navrangpura, Ahmedabad 380009, IndiaDepartment of Astronomy and Astrophysics, Tata Institute of Fundamental Research , Homi Bhabha Road, Mumbai 400005, IndiaS.N. Bose National Centre for Basic Sciences , Block JD, Sector III, Salt Lake, Kolkata 700106, West Bengal, IndiaInstitute of Applied Physics of the Russian Academy of Sciences , 46 Ul’yanov str., 603950 Nizhny Novgorod, RussiaWe present a molecular line study of the Sh2-138 (IRAS 22308+5812) hub-filament system with the aim of investigating its structure and kinematics. Archival CO molecular line data from the Canadian Galactic Plane Survey (CO( J = 1–0)) for the wider region (∼50′ × 50′) and the James Clerk Maxwell Telescope (CO(3–2), ^13 CO(3–2), and C ^18 O(3–2)) for the central portion (∼5′ × 5′) have been utilized. Analysis of the CO(1–0) spectra for the extended region in conjunction with the identification of the hub and filament using a column density map and the getsf tool, respectively, reveals a complex structure with the spectral extraction for the central position displaying multiple velocity components. Based on the Herschel 70 μ m warm dust emission, one of the filaments in the extended region was inferred to be associated with active star formation, and is host to a Bolocam 1.1 mm clump of ∼1606 M _☉ . An integrated intensity map of ^13 CO(3–2) emission, constructed from clumps detected at above 5 σ in position–position–velocity space, reveals three filamentary structures (labeled the western filament (W-f), southwestern filament (SW-f), and southeast filament (SE-f)) in the central portion. Velocity gradients observed in ^13 CO(3–2) position–velocity slices point to longitudinal gas flow along the filaments into the central region. Filaments W-f, SW-f, and SE-f were calculated to have observed line masses of ∼32, 33.5, and 50 M _☉ pc ^−1 , respectively. The cloud was found to be dominated by supersonic and nonthermal motions, with high Mach numbers (≳3) and a low thermal-to-nonthermal pressure ratio (∼0.01–0.1).https://doi.org/10.3847/1538-4357/acb8bcInterstellar mediumInterstellar filamentsInterstellar moleculesH II regionsMillimeter astronomyStar formation |
| spellingShingle | Kshitiz K. Mallick Lokesh K. Dewangan Devendra K. Ojha Tapas Baug Igor I. Zinchenko Structure and Kinematics of Sh2-138—A Distant Hub-filament System in the Outer Galactic Plane The Astrophysical Journal Interstellar medium Interstellar filaments Interstellar molecules H II regions Millimeter astronomy Star formation |
| title | Structure and Kinematics of Sh2-138—A Distant Hub-filament System in the Outer Galactic Plane |
| title_full | Structure and Kinematics of Sh2-138—A Distant Hub-filament System in the Outer Galactic Plane |
| title_fullStr | Structure and Kinematics of Sh2-138—A Distant Hub-filament System in the Outer Galactic Plane |
| title_full_unstemmed | Structure and Kinematics of Sh2-138—A Distant Hub-filament System in the Outer Galactic Plane |
| title_short | Structure and Kinematics of Sh2-138—A Distant Hub-filament System in the Outer Galactic Plane |
| title_sort | structure and kinematics of sh2 138 a distant hub filament system in the outer galactic plane |
| topic | Interstellar medium Interstellar filaments Interstellar molecules H II regions Millimeter astronomy Star formation |
| url | https://doi.org/10.3847/1538-4357/acb8bc |
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