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dc.contributor.authorHayes, Christian R.
dc.contributor.authorMajewski, Steven R.
dc.contributor.authorHasselquist, Sten
dc.contributor.authorBeaton, R. L.
dc.contributor.authorCunha, Katia
dc.contributor.authorSmith, Verne V.
dc.contributor.authorPrice-Whelan, Adrian M.
dc.contributor.authorAnguiano, Borja
dc.contributor.authorBeers, Timothy C.
dc.contributor.authorCarrera, Ricardo
dc.contributor.authorFernández-Trincado, J. G.
dc.contributor.authorFrinchaboy, Peter M.
dc.contributor.authorGarcía-Hernández, D. A.
dc.contributor.authorLane, Richard R.
dc.contributor.authorNidever, David L.
dc.contributor.authorNitschelm, Christian
dc.contributor.authorRoman-Lopes, Alexandre
dc.contributor.authorZamora, Olga
dc.date.accessioned2018-07-24T23:26:16Z
dc.date.available2018-07-24T23:26:16Z
dc.date.issued2018-05-20
dc.identifier.citationChristian R. Hayes et al 2018 ApJL 859 L8en_US
dc.identifier.issn2041-8213
dc.identifier.doi10.3847/2041-8213/aac38c
dc.identifier.urihttp://hdl.handle.net/10150/628290
dc.description.abstractThe nature of the Triangulum-Andromeda (TriAnd) system has been debated since the discovery of this distant, low-latitude Milky Way (MW) overdensity more than a decade ago. Explanations for its origin are either as a halo substructure from the disruption of a dwarf galaxy, or a distant extension of the Galactic disk. We test these hypotheses using the chemical abundances of a dozen TriAnd members from the Sloan Digital Sky Survey-IV's (SDSS-IV's) 14th Data Release (DR14) of Apache Point Observatory Galactic Evolution Experiment (APOGEE) data to compare to APOGEE abundances of stars with similar metallicity from both the Sagittarius (Sgr) dSph and the outer MW disk. We find that TriAnd stars are chemically distinct from Sgr across a variety of elements, (C+N), Mg, K, Ca, Mn, and Ni, with a separation in [X/Fe] of about 0.1 to 0.4 dex depending on the element. Instead, the TriAnd stars, with a median metallicity of about -0.8, exhibit chemical abundance ratios similar to those of the lowest metallicity ([Fe/H] similar to-0.7)stars in the outer Galactic disk, and are consistent with expectations of extrapolated chemical gradients in the outer disk of the MW. These results suggest that TriAnd is associated with the MW disk, and, therefore, that the disk extends to this overdensity-i.e., past a Galactocentric radius of 24 kpc -albeit vertically perturbed about 7 kpc below the nominal disk midplane in this region of the Galaxy.en_US
dc.description.sponsorshipNSF [DGE-1315231, AST-1312863, AST-1616636]; NASA by the Space Telescope Science Institute [51386.01]; FONDECYT [3180210]; Spanish Ministry of Economy and Competitiveness (MINECO) [AYA-2017-88254-P]; Physics Frontier Center/JINA-CEE - U.S. National Science Foundation [PHY 14-30152]; Alfred P. Sloan Foundation; U.S. Department of Energy Office of Science; Center for High-Performance Computing at the University of Utah; Brazilian Participation Group; Carnegie Institution for Science, Carnegie Mellon University; Chilean Participation Group; French Participation Group; Harvard-Smithsonian Center for Astrophysics; Instituto de Astrofisica de Canarias; Johns Hopkins University; Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo; Lawrence Berkeley National Laboratory; Leibniz Institut fur Astrophysik Potsdam (AIP); Max-Planck-Institut fur Astronomie (MPIA Heidelberg); Max-Planck-Institut fur Astrophysik (MPA Garching); Max-Planck-Institut fur Extraterrestrische Physik (MPE); National Astronomical Observatories of China; New Mexico State University; New York University; University of Notre Dame; Observatario Nacional/MCTI; Ohio State University; Pennsylvania State University; Shanghai Astronomical Observatory; United Kingdom Participation Group; Universidad Nacional Autonoma de Mexico; University of Arizona; University of Colorado Boulder; University of Oxford; University of Portsmouth; University of Utah; University of Virginia; University of Washington; University of Wisconsin; Vanderbilt University; Yale University; NASA [NAS 5-26555]en_US
dc.language.isoenen_US
dc.publisherIOP PUBLISHING LTDen_US
dc.relation.urlhttp://stacks.iop.org/2041-8205/859/i=1/a=L8?key=crossref.b3736b8adb3bce16e04c556b276fc153en_US
dc.rights© 2018. The American Astronomical Society. All rights reserved.en_US
dc.subjectGalaxy: disken_US
dc.subjectGalaxy: evolutionen_US
dc.subjectGalaxy: haloen_US
dc.subjectGalaxy: structureen_US
dc.subjectstars: abundancesen_US
dc.titleDisk-like Chemistry of the Triangulum-Andromeda Overdensity as Seen by APOGEEen_US
dc.typeArticleen_US
dc.contributor.departmentUniv Arizona, Steward Observen_US
dc.identifier.journalASTROPHYSICAL JOURNAL LETTERSen_US
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en_US
dc.eprint.versionFinal published versionen_US
dc.source.journaltitleThe Astrophysical Journal
dc.source.volume859
dc.source.issue1
dc.source.beginpageL8
refterms.dateFOA2018-07-24T23:26:17Z


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