RECONSTRUCTING THE ACCRETION HISTORY OF THE GALACTIC STELLAR HALO FROM CHEMICAL ABUNDANCE RATIO DISTRIBUTIONS
文献类型:期刊论文
作者 | Lee, Duane M.1; Johnston, Kathryn V.2; Sen, Bodhisattva3; Jessop, Will3 |
刊名 | ASTROPHYSICAL JOURNAL
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出版日期 | 2015-03-20 |
卷号 | 802期号:1页码:1 |
关键词 | Galaxy: abundances Galaxy: halo Galaxy: stellar content galaxies: dwarf methods: statistical stars: abundances |
英文摘要 | Observational studies of halo stars during the past two decades have placed some limits on the quantity and nature of accreted dwarf galaxy contributions to the Milky Way (MW) stellar halo by typically utilizing stellar phase-space information to identify the most recent halo accretion events. In this study we tested the prospects of using 2D chemical abundance ratio distributions (CARDs) found in stars of the stellar halo to determine its formation history. First, we used simulated data from 11 "MW-like" halos to generate satellite template sets (STSs) of 2D CARDs of accreted dwarf satellites, which are composed of accreted dwarfs from various mass regimes and epochs of accretion. Next, we randomly drew samples of similar to 10(3-4) mock observations of stellar chemical abundance ratios ([alpha/Fe], [Fe/H]) from those 11 halos to generate samples of the underlying densities for our CARDs to be compared to our templates in our analysis. Finally, we used the expectation-maximization algorithm to derive accretion histories in relation to the STS used and the sample size. For certain STSs used we typically can identify the relative mass contributions of all accreted satellites to within a factor of two. We also find that this method is particularly sensitive to older accretion events involving low-luminosity dwarfs, e.g., ultra-faint dwarfs-precisely those events that are too ancient to be seen by phase-space studies of stars and too faint to be seen by high-z studies of the early universe. Since our results only exploit two chemical dimensions and near-future surveys promise to provide similar to 6-9 dimensions, we conclude that these new high-resolution spectroscopic surveys of the stellar halo will allow us to recover its accretion history-and the luminosity function of infalling dwarf galaxies-across cosmic time. |
WOS标题词 | Science & Technology ; Physical Sciences |
类目[WOS] | Astronomy & Astrophysics |
研究领域[WOS] | Astronomy & Astrophysics |
关键词[WOS] | DWARF SPHEROIDAL GALAXY ; METAL-POOR STARS ; ALL-SKY SURVEY ; MILKY-WAY ; GLOBULAR-CLUSTERS ; GIANT STARS ; COLD HALO ; SAGITTARIUS ; FIELD ; DISK |
收录类别 | SCI |
语种 | 英语 |
WOS记录号 | WOS:000351834700048 |
公开日期 | 2015-08-18 |
源URL | [http://119.78.226.72/handle/331011/18225] ![]() |
专题 | 上海天文台_星系宇宙学重点实验室 |
作者单位 | 1.Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China 2.Columbia Univ, Dept Astron, New York, NY 10027 USA 3.Columbia Univ, Dept Stat, New York, NY 10027 USA |
推荐引用方式 GB/T 7714 | Lee, Duane M.,Johnston, Kathryn V.,Sen, Bodhisattva,et al. RECONSTRUCTING THE ACCRETION HISTORY OF THE GALACTIC STELLAR HALO FROM CHEMICAL ABUNDANCE RATIO DISTRIBUTIONS[J]. ASTROPHYSICAL JOURNAL,2015,802(1):1. |
APA | Lee, Duane M.,Johnston, Kathryn V.,Sen, Bodhisattva,&Jessop, Will.(2015).RECONSTRUCTING THE ACCRETION HISTORY OF THE GALACTIC STELLAR HALO FROM CHEMICAL ABUNDANCE RATIO DISTRIBUTIONS.ASTROPHYSICAL JOURNAL,802(1),1. |
MLA | Lee, Duane M.,et al."RECONSTRUCTING THE ACCRETION HISTORY OF THE GALACTIC STELLAR HALO FROM CHEMICAL ABUNDANCE RATIO DISTRIBUTIONS".ASTROPHYSICAL JOURNAL 802.1(2015):1. |
入库方式: OAI收割
来源:上海天文台
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