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A high pitch angle structure in the Sagittarius Arm
Kuhn, M. A.1; Benjamin, R. A.2; Zucker, C.3; Krone-Martins, A.4,5; de Souza, R. S.6; Castro-Ginard, A.7; Ishida, E. E. O.8; Povich, M. S.9; Hillenbrand, L. A.1
2021-07-21
Source PublicationASTRONOMY & ASTROPHYSICS
ISSN0004-6361
Volume651Pages:13
AbstractContext. In spiral galaxies, star formation tends to trace features of the spiral pattern, including arms, spurs, feathers, and branches. However, in our own Milky Way, it has been challenging to connect individual star-forming regions to their larger Galactic environment owing to our perspective from within the disk. One feature in nearly all modern models of the Milky Way is the Sagittarius Arm, located inward of the Sun with a pitch angle of similar to 12 degrees .Aims. We map the 3D locations and velocities of star-forming regions in a segment of the Sagittarius Arm using young stellar objects (YSOs) from the Spitzer/IRAC Candidate YSO (SPICY) catalog to compare their distribution to models of the arm.Methods. Distances and velocities for these objects are derived from Gaia EDR3 astrometry and molecular line surveys. We infer parallaxes and proper motions for spatially clustered groups of YSOs and estimate their radial velocities from the velocities of spatially associated molecular clouds.Results. We identify 25 star-forming regions in the Galactic longitude range l similar to 4.degrees 0-18.degrees 5 arranged in a narrow, similar to 1 kpc long linear structure with a high pitch angle of =56 degrees and a high aspect ratio of similar to 7:1. This structure includes massive star-forming regions such as M8, M16, M17, and M20. The motions in the structure are remarkably coherent, with velocities in the direction of Galactic rotation of |V-phi|approximate to 240 +/- 3 km s(-1) (slightly higher than average) and slight drifts inward (V-R approximate to -4.3 km s(-1)) and in the negative Z direction (V-Z approximate to -2.9 km s(-1)). The rotational shear experienced by the structure is Delta Omega =4.6 km s(-1) kpc(-1).Conclusions. The observed 56 degrees pitch angle is remarkably high for a segment of the Sagittarius Arm. We discuss possible interpretations of this feature as a substructure within the lower pitch angle Sagittarius Arm, as a spur, or as an isolated structure.
KeywordGalaxy: structure Galaxy: kinematics and dynamics galaxies: spiral ISM: clouds stars: formation
Funding OrganizationChandra grant ; Chandra grant ; NASA ; NASA ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Chandra grant ; Chandra grant ; NASA ; NASA ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Chandra grant ; Chandra grant ; NASA ; NASA ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Chandra grant ; Chandra grant ; NASA ; NASA ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT)
DOI10.1051/0004-6361/202141198
WOS KeywordSTAR-FORMING REGIONS ; MOLECULAR CLOUDS ; TRIGONOMETRIC PARALLAXES ; SPIRAL STRUCTURE ; DATA RELEASE ; GALAXY ; HYDROGEN ; SPURS ; GAS ; MAP
Language英语
Funding ProjectChandra grant[GO9-20002X] ; NASA[NNX17AJ27G] ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT)[UID/FIS/00099/2019] ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT)[PTDC/FISAST/31546/2017]
Funding OrganizationChandra grant ; Chandra grant ; NASA ; NASA ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Chandra grant ; Chandra grant ; NASA ; NASA ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Chandra grant ; Chandra grant ; NASA ; NASA ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Chandra grant ; Chandra grant ; NASA ; NASA ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) ; Portuguese Fundacao para a Ciencia e a Tecnologia (FCT)
WOS Research AreaAstronomy & Astrophysics
WOS SubjectAstronomy & Astrophysics
WOS IDWOS:000678074800001
PublisherEDP SCIENCES S A
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Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/76184
Collection中国科学院国家天文台
Corresponding AuthorKuhn, M. A.
Affiliation1.CALTECH, Pasadena, CA 91125 USA
2.Univ Wisconsin Whitewater, Dept Phys, 800 W Main St, Whitewater, WI 53190 USA
3.Ctr Astrophys & Harvard & Smithsonian, 60 Garden St, Cambridge, MA 02138 USA
4.Univ Calif Irvine, Donald Bren Sch Informat & Comp Sci, Irvine, CA 92697 USA
5.Univ Lisbon, Fac Ciencias, CENTRA SIM, Ed C8, P-1749016 Lisbon, Portugal
6.Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, 80 Nandan Rd, Shanghai 200030, Peoples R China
7.Univ Barcelona IEEC UB, Inst Ciencies Cosmos, Marti i Franques 1, Barcelona 08028, Spain
8.Univ Clermont Auvergne, LPC, CNRS, IN2P3, F-63000 Clermont Ferrand, France
9.Calif State Polytech Univ Pomona, Dept Phys & Astron, 3801 West Temple Ave, Pomona, CA 91768 USA
Recommended Citation
GB/T 7714
Kuhn, M. A.,Benjamin, R. A.,Zucker, C.,et al. A high pitch angle structure in the Sagittarius Arm[J]. ASTRONOMY & ASTROPHYSICS,2021,651:13.
APA Kuhn, M. A..,Benjamin, R. A..,Zucker, C..,Krone-Martins, A..,de Souza, R. S..,...&Hillenbrand, L. A..(2021).A high pitch angle structure in the Sagittarius Arm.ASTRONOMY & ASTROPHYSICS,651,13.
MLA Kuhn, M. A.,et al."A high pitch angle structure in the Sagittarius Arm".ASTRONOMY & ASTROPHYSICS 651(2021):13.
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