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The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2
Amarante, Joao A. S.1; Smith, Martin C.1; Boeche, Corrado2
2020-03-01
Source PublicationMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
ISSN0035-8711
Volume492Issue:3Pages:3816-3828
AbstractAlthough the stellar halo accounts for just similar to 1 per cent of the total stellar mass of the Milky Way, the kinematics of halo stars encode valuable information about the origins and evolution of our Galaxy. It has been shown that the high transverse velocity stars in Gaia DR2 reveal a double sequence in the Hertzsprung-Russell (HR) diagram, indicating a bifurcation in the local stellar halo within 1 kpc. We fit these stars by updating the popular-Besancon/Galaxia model, incorporating the latest observational results for the stellar halo and an improved kinematic description for the thick disc from Schonrich & Binney (2012). We are able to obtain a good match to the Gaia data and provide new constraints on the properties of the Galactic disc and stellar halo. In particular, we show that the kinematically defined thick-disc contribution to this high velocity tail is approximate to 13 per cent. We look in greater detail using chemistry from LAMOST DR5, identifying a population of retrograde stars with thick-disc chemistry. Our thick-disc kinematic model cannot account for this population and so we conclude there is likely to be a contribution from heated or accreted stars in the Solar Neighbourhood. We also investigate proposed dynamical substructures in this sample, concluding that they are probably due to resonant orbits rather than accreted populations. Finally, we provide new insights on the nature of the two sequences and their relation with past accretion events and the primordial Galactic disc.
KeywordGalaxy: disc Galaxy: halo Galaxy: kinematics and dynamics
Funding OrganizationNational Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences
DOI10.1093/mnras/staa077
WOS KeywordMILKY-WAY TOMOGRAPHY ; STELLAR HALO ; PHASE-SPACE ; DISC ; THICK ; GALAXY ; KINEMATICS ; POPULATIONS ; DISTANCES ; ORIGIN
Language英语
Funding ProjectNational Key Basic Research and Development Program of China[2018YFA0404501] ; NSFC[11673083] ; The World Academy of Sciences ; Chinese Academy of Sciences
Funding OrganizationNational Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences
WOS Research AreaAstronomy & Astrophysics
WOS SubjectAstronomy & Astrophysics
WOS IDWOS:000518143200054
PublisherOXFORD UNIV PRESS
Citation statistics
Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/54499
Collection中国科学院国家天文台
Corresponding AuthorAmarante, Joao A. S.
Affiliation1.Chinese Acad Sci, Key Lab Res Galaxies & Cosmol, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China
2.INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy
Recommended Citation
GB/T 7714
Amarante, Joao A. S.,Smith, Martin C.,Boeche, Corrado. The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2020,492(3):3816-3828.
APA Amarante, Joao A. S.,Smith, Martin C.,&Boeche, Corrado.(2020).The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,492(3),3816-3828.
MLA Amarante, Joao A. S.,et al."The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 492.3(2020):3816-3828.
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