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dc.contributor.authorLimberg, Guilherme
dc.contributor.authorRossi, Silvia
dc.contributor.authorBeers, Timothy
dc.contributor.authorPerottoni, Helio
dc.contributor.authorPerez-Villegas, Angeles
dc.contributor.authorSantucci, Rafael
dc.contributor.authorAbuchaim, Yuri
dc.contributor.authorPlacco, Vinicius
dc.contributor.authorLee, Young Sun
dc.contributor.authorChristlieb, Norbert
dc.contributor.authorNorris, John
dc.contributor.authorBessell, Michael
dc.contributor.authorRyan, Sean
dc.contributor.authorWilhelm, Ronald
dc.contributor.authorRhee, Jaehyon
dc.contributor.authorFrebel, Anna
dc.date.accessioned2021-01-27T20:15:23Z
dc.date.available2021-01-27T20:15:23Z
dc.date.issued2021-01-20
dc.identifier.citationLimberg , G , Rossi , S , Beers , T , Perottoni , H , Perez-Villegas , A , Santucci , R , Abuchaim , Y , Placco , V , Lee , Y S , Christlieb , N , Norris , J , Bessell , M , Ryan , S , Wilhelm , R , Rhee , J & Frebel , A 2021 , ' Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys ' , The Astrophysical Journal , vol. 907 , no. 1 , 10 . https://doi.org/10.3847/1538-4357/abcb87
dc.identifier.issn0004-637X
dc.identifier.otherPURE: 23021072
dc.identifier.otherPURE UUID: 087b1dbc-1b45-467a-ae0c-c0fcd68ea4f6
dc.identifier.otherORCID: /0000-0001-9069-5122/work/87789559
dc.identifier.otherScopus: 85100987483
dc.identifier.urihttp://hdl.handle.net/2299/23772
dc.description© 2020. The American Astronomical Society. All rights reserved.
dc.description.abstractWe analyze the dynamical properties of ∼1500 very metal-poor (VMP; [Fe/H] ≲−2.0) halo stars, based primarily on medium-resolution spectroscopic data from the HK and Hamburg/ESO surveys. These data, collected over the past thirty years, are supplemented by a number of calibration stars and other small samples, along with astrometric information from Gaia DR2. We apply a clustering algorithm to the 4-D energy-action space of the sample, and identify a set of 38 Dynamically Tagged Groups (DTGs), containing between 5 and 30 member stars. Many of these DTGs can be associated with previously known prominent substructures such as Gaia-Sausage/Enceladus (GSE), Sequoia, the Helmi Stream (HStr), and Thamnos. Others are associated with previously identified smaller dynamical groups of stars and streams. We identify 10 new DTGs as well, many of which have strongly retrograde orbits. We also investigate possible connections between our DTGs and ∼300 individual r-process-enhanced (RPE) stars \textbf{from a recent literature compilation}. We find that several of these objects have similar dynamical properties to GSE (5), the HStr (4), Sequoia (1), and Rg5 (1), indicating that their progenitors might have been important sources of RPE stars in the Galaxy. Additionally, a number of our newly identified DTGs are shown to be associated with at least two RPE stars each (DTG-2: 3, DTG-7: 2; DTG-27: 2). Taken as a whole, these results are consistent with ultra-faint and/or dwarf spheroidal galaxies as birth environments in which r-process nucleosynthesis took place, and then were disrupted by the Milky Way.en
dc.format.extent25
dc.language.isoeng
dc.relation.ispartofThe Astrophysical Journal
dc.subjectGalaxy: stellar halo
dc.subjectGalaxy: formation
dc.subjectGalaxy: kinematics and dynamics
dc.subjectStars: very metal-poor
dc.subjectChemical Evolution: r-process
dc.subjectStellar Populations: Population II
dc.subjectAstronomy and Astrophysics
dc.titleDynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveysen
dc.contributor.institutionCentre for Astrophysics Research
dc.contributor.institutionSchool of Physics, Engineering & Computer Science
dc.contributor.institutionPhysics, Astronomy and Mathematics
dc.description.statusPeer reviewed
rioxxterms.versionAM
rioxxterms.versionofrecordhttps://doi.org/10.3847/1538-4357/abcb87
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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