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The GALAH survey: Properties of the Galactic disc(s) in the solar neighbourhood

Duong, Ly; Freeman, Kenneth; Asplund, Martin; Casagrande, Luca; Lin, Jinying (Jane); Schlesinger, Katharine; Da Costa, Gary; Nataf, David; Ting, Yuan; Lind, Karin; Bland-Hawthorn, Joss; Lewis, Geraint Francis; Sharma, S; Zwitter, T; Kafle, P R; Reid, W; Stello, Dennis; Wyse, Rosemary F G

Description

Using data from the GALAH pilot survey, we determine properties of the Galactic thin and thick discs near the solar neighbourhood. The data cover a small range of Galactocentric radius (7.9 RGC 9.5 kpc), but extend up to 4 kpc in height from the Galactic plane, and several kpc in the direction of Galactic anti-rotation (at longitude 260◦ ≤ ≤ 280◦). This allows us to reliably measure the vertical density and abundance profiles of the chemically and kinematically defined ‘thick’ and ‘thin’...[Show more]

dc.contributor.authorDuong, Ly
dc.contributor.authorFreeman, Kenneth
dc.contributor.authorAsplund, Martin
dc.contributor.authorCasagrande, Luca
dc.contributor.authorLin, Jinying (Jane)
dc.contributor.authorSchlesinger, Katharine
dc.contributor.authorDa Costa, Gary
dc.contributor.authorNataf, David
dc.contributor.authorTing, Yuan
dc.contributor.authorLind, Karin
dc.contributor.authorBland-Hawthorn, Joss
dc.contributor.authorLewis, Geraint Francis
dc.contributor.authorSharma, S
dc.contributor.authorZwitter, T
dc.contributor.authorKafle, P R
dc.contributor.authorReid, W
dc.contributor.authorStello, Dennis
dc.contributor.authorWyse, Rosemary F G
dc.date.accessioned2020-04-20T01:53:05Z
dc.date.available2020-04-20T01:53:05Z
dc.identifier.issn0035-8711
dc.identifier.urihttp://hdl.handle.net/1885/203257
dc.description.abstractUsing data from the GALAH pilot survey, we determine properties of the Galactic thin and thick discs near the solar neighbourhood. The data cover a small range of Galactocentric radius (7.9 RGC 9.5 kpc), but extend up to 4 kpc in height from the Galactic plane, and several kpc in the direction of Galactic anti-rotation (at longitude 260◦ ≤ ≤ 280◦). This allows us to reliably measure the vertical density and abundance profiles of the chemically and kinematically defined ‘thick’ and ‘thin’ discs of the Galaxy. The thin disc (low-α population) exhibits a steep negative vertical metallicity gradient, at d[M/H]/dz = −0.18 ± 0.01 dex kpc−1, which is broadly consistent with previous studies. In contrast, its vertical α-abundance profile is almost flat, with a gradient of d[α/M]/dz = 0.008 ± 0.002 dex kpc−1. The steep vertical metallicity gradient of the low-α population is in agreement with models where radial migration has a major role in the evolution of the thin disc. The thick disc (high-α population) has a weaker vertical metallicity gradient d[M/H]/dz = −0.058 ± 0.003 dex kpc−1. The αabundance of the thick disc is nearly constant with height, d[α/M]/dz = 0.007 ± 0.002 dex kpc−1. The negative gradient in metallicity and the small gradient in [α/M] indicate that the high-α population experienced a settling phase, but also formed prior to the onset of major Type Ia supernova enrichment. We explore the implications of the distinct α-enrichments and narrow [α/M] range of the sub-populations in the context of thick disc formation.
dc.description.sponsorshipLD and MA acknowledge funding from the Australian Government through ARC Laureate Fellowship FL110100012. LD, KCF, and RFGW acknowledge support from ARC grant DP160103747. LC gratefully acknowledges support from the Australian Research Council (grants DP150100250, FT160100402). DMN was supported by the Allan C. and Dorothy H. Davis Fellowship. DS is the recipient of an Australian Research Council Future Fellowship (project number FT1400147). TZ acknowledges financial support from the Slovenian Research Agency (research core funding No. P1-0188). Part of this research was supported by the Munich Institute for Astro- and Particle Physics (MIAPP) of the DFG cluster of excellence ‘Origin and Structure of the Universe’.
dc.format.extent17 pages
dc.format.mimetypeapplication/pdf
dc.language.isoen_AU
dc.publisherOxford University Press (OUP)
dc.rights© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. https://academic.oup.com/journals/pages/self_archiving_policy_p This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 L Duong, K C Freeman, M Asplund, L Casagrande, S Buder, K Lind, M Ness, J Bland-Hawthorn, G M De Silva, V D'Orazi, J Kos, G F Lewis, J Lin, S L Martell, K Schlesinger, S Sharma, J D Simpson, D B Zucker, T Zwitter, B Anguiano, G S Da Costa, E Hyde, J Horner, P R Kafle, D M Nataf, W Reid, D Stello, Y-S Ting, R F G Wyse Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved (Publisher journal website as of 20/4/2020)
dc.sourceMonthly Notices of the Royal Astronomical Society
dc.subjectsurveys, stars, abundances, Galaxy, disc- Galaxy, evolution, formation.
dc.titleThe GALAH survey: Properties of the Galactic disc(s) in the solar neighbourhood
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume476
dcterms.dateAccepted2018-02-22
dc.date.issued2018-06
local.identifier.absfor020110 - Stellar Astronomy and Planetary Systems
local.identifier.absfor020104 - Galactic Astronomy
local.identifier.ariespublicationu4485658xPUB233
local.publisher.urlhttps://academic.oup.com/
local.type.statusPublished Version
local.contributor.affiliationDuong, Ly, College of Science, The Australian National University
local.contributor.affiliationFreeman, Kenneth, College of Science, The Australian National University
local.contributor.affiliationAsplund, Martin, College of Science, The Australian National University
local.contributor.affiliationCasagrande, Luca, College of Science, The Australian National University
local.contributor.affiliationLin, Jinying (Jane), College of Science, The Australian National University
local.contributor.affiliationSchlesinger, Katharine, College of Science, The Australian National University
local.contributor.affiliationDa Costa, Gary, College of Science, The Australian National University
local.contributor.affiliationNataf, David, College of Science, The Australian National University
local.contributor.affiliationTing, Yuan, College of Science, The Australian National University
local.contributor.affiliationLind, Karin, Max Planck Institut fur Astrophysik
local.contributor.affiliationBland-Hawthorn, Joss, University of Sydney
local.contributor.affiliationLewis, Geraint Francis, University of Sydney
local.contributor.affiliationSharma, S, University of Sydney
local.contributor.affiliationZwitter, T, University of Ljubljana
local.contributor.affiliationKafle, P R, The University of Western Australia
local.contributor.affiliationReid, W, Macquarie University
local.contributor.affiliationStello, Dennis, University of Sydney
local.contributor.affiliationWyse, Rosemary F G, Johns Hopkins University
dc.relationhttp://purl.org/au-research/grants/arc/FL110100012
dc.relationhttp://purl.org/au-research/grants/arc/DP160103747
dc.relationhttp://purl.org/au-research/grants/arc/DP150100250
dc.relationhttp://purl.org/au-research/grants/arc/FT160100402
dc.relationhttp://purl.org/au-research/grants/arc/FT1400147
local.identifier.essn1365-2966
local.bibliographicCitation.issue4
local.bibliographicCitation.startpage5216
local.bibliographicCitation.lastpage5232
local.identifier.doi10.1093/MNRAS/STY525
local.identifier.absseo970102 - Expanding Knowledge in the Physical Sciences
dc.date.updated2019-11-25T07:53:56Z
local.identifier.scopusID2-s2.0-85048491959
dcterms.accessRightsOpen Access
dc.provenancehttp://sherpa.ac.uk/romeo/issn/0035-8711/ Author can archive publisher's version/PDF. Publisher's version/PDF may be used.
CollectionsANU Research Publications

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