Mapping the Milky Way with LAMOST - III. Complicated spatial structure in the outer disc

doi:10.1093/mnras/sty1058

CORC > 国家天文台 > 中国科学院国家天文台

	Mapping the Milky Way with LAMOST - III. Complicated spatial structure in the outer disc
	Wang, Hai-Feng 1,2; Liu, Chao 1,2; Xu, Yan 1; Wan, Jun-Chen 1; Deng, Licai 1
刊名	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2018-08-01
卷号	478 期号:3 页码:3367-3379
关键词	Galaxy: disc Galaxy: evolution Galaxy: structure
ISSN号	0035-8711
DOI	10.1093/mnras/sty1058
英文摘要	We illustrate the complexity of the Galactic outer disc by fitting the stellar volume densities of red giant branch stars with a two-disc component model. The discs are confirmed to extend to R similar to 19 kpc. The radial density profile of the discs shows two breaks at R similar to 11 and similar to 14 kpc, respectively, which separate the radial profile into three segments with different scalelengths of 2.12 +/- 0.26, 1.18 +/- 0.08 and 2.72 kpc at R < 11, 11 <= R <= 14 and R > 14 kpc, respectively. The first break is likely due to the sudden drop in the radial profile of the thin disc, which may be evidence of radial migration. Beyond 14 kpc, the thick disc becomes prominent and the transition from a thin to a thick disc leads to the second break. This implies that the geometrically defined thick disc is more radially extended than the thin disc. This is also supported by the larger scalelength of the thick disc in comparison with the thin disc. Meanwhile, the scaleheight of the thicker component increases from 0.637(-0.036)(+0.056) at R = 8 to 1.284(-0.079)(+0.086) kpc at R = 19 kpc, showing an intensive flared disc. Moreover, rich substructures are displayed in the residuals of stellar density. Among them, the substructures D14 + 2.0 and O14 - 1.5 show a north-south asymmetry, which can essentially be explained by southward shifting of the thick disc. However, no significant overdensity is found for the Monoceros ring. Finally, the thick disc shows a ripple-like feature with unclear origin at 9 < R < 10.5 kpc.
资助项目	National Key Basic Research Program of China[2014CB845700] ; NSFC[11373032] ; NSFC[11333003] ; National Development and Reform Commission
WOS关键词	SPIRAL GALAXIES ; GALACTIC DISCS ; DWARF GALAXY ; THICK DISKS ; CANIS MAJOR ; SDSS ; STARS ; SAGITTARIUS ; DENSITY ; 2MASS
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	OXFORD UNIV PRESS
WOS记录号	WOS:000441282300036
资助机构	National Key Basic Research Program of China ; National Key Basic Research Program of China ; NSFC ; NSFC ; National Development and Reform Commission ; National Development and Reform Commission ; National Key Basic Research Program of China ; National Key Basic Research Program of China ; NSFC ; NSFC ; National Development and Reform Commission ; National Development and Reform Commission ; National Key Basic Research Program of China ; National Key Basic Research Program of China ; NSFC ; NSFC ; National Development and Reform Commission ; National Development and Reform Commission ; National Key Basic Research Program of China ; National Key Basic Research Program of China ; NSFC ; NSFC ; National Development and Reform Commission ; National Development and Reform Commission
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/22482]
专题	中国科学院国家天文台
通讯作者	Liu, Chao
作者单位	1.Chinese Acad Sci, Key Lab Opt Astron, Natl Astron Observ, Beijing 100012, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Wang, Hai-Feng,Liu, Chao,Xu, Yan,et al. Mapping the Milky Way with LAMOST - III. Complicated spatial structure in the outer disc[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2018,478(3):3367-3379.
APA	Wang, Hai-Feng,Liu, Chao,Xu, Yan,Wan, Jun-Chen,&Deng, Licai.(2018).Mapping the Milky Way with LAMOST - III. Complicated spatial structure in the outer disc.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,478(3),3367-3379.
MLA	Wang, Hai-Feng,et al."Mapping the Milky Way with LAMOST - III. Complicated spatial structure in the outer disc".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 478.3(2018):3367-3379.