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Article: Asymmetric metallicity patterns in the stellar velocity space with RAVE

TitleAsymmetric metallicity patterns in the stellar velocity space with RAVE
Authors
KeywordsGalaxy: kinematics and dynamics
Galaxy: structure
Galaxy: disk
Galaxy: evolution
Galaxy: abundances
Issue Date2017
PublisherEDP Sciences. The Journal's web site is located at http://www.aanda.org
Citation
Astronomy & Astrophysics, 2017, v. 601, article no. A59, p. 1-10 How to Cite?
AbstractContext. The chemical abundances of stars encode information on their place and time of origin. Stars formed together in e.g. a cluster, should present chemical homogeneity. Also disk stars influenced by the effects of the bar and the spiral arms might have distinct chemical signatures depending on the type of orbit that they follow, e.g. from the inner versus outer regions of the Milky Way. Aims. We explore the correlations between velocity and metallicity and the possible distinct chemical signatures of the velocity over-densities of the local Galactic neighbourhood. Methods. We use the large spectroscopic survey RAVE and the Geneva Copenhagen Survey. We compare the metallicity distribution of regions in the velocity plane (vR,vφ) with that of their symmetric counterparts (−vR,vφ). We expect similar metallicity distributions if there are no tracers of a sub-population (e.g. a dispersed cluster, accreted stars), if the disk of the Galaxy is axisymmetric, and if the orbital effects of the bar and the spiral arms are weak. Results. We find that the metallicity-velocity space of the solar neighbourhood is highly patterned. A large fraction of the velocity plane shows differences in the metallicity distribution when comparing symmetric vR regions. The typical differences in the median metallicity are of 0.05 dex with statistical significant of at least 95% confidence, and with values up to 0.6 dex. For stars with low azimuthal velocity vφ, the ones moving outwards. These include stars in the Hercules and Hyades moving groups and other velocity branch-like structures. For higher vφ, the stars moving inwards have higher metallicity than those moving outwards. We have also discovered a positive gradient in vφ with respect to metallicity at high metallicities, apart from the two known positive and negative gradients for the thick and thin disks. Conclusions. The most likely interpretation of the metallicity asymmetry is that it is mainly due to the orbital effects of the Galactic bar and the radial metallicity gradient of the disk. We present a simulation that supports this idea.
Persistent Identifierhttp://hdl.handle.net/10722/242102
ISSN
2019 Impact Factor: 5.636
2015 SCImago Journal Rankings: 2.446
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorAntoja, T-
dc.contributor.authorKordopatis, G-
dc.contributor.authorHelmi, A-
dc.contributor.authorMonari, G-
dc.contributor.authorFamaey, B-
dc.contributor.authorWyse, RFG-
dc.contributor.authorGrebel, EK-
dc.contributor.authorSteinmetz, M-
dc.contributor.authorBland-Hawthorn, J-
dc.contributor.authorGibson, BK-
dc.contributor.authorBienaymé, O-
dc.contributor.authorNavarro, JF-
dc.contributor.authorParker, QA-
dc.contributor.authorReid, W-
dc.contributor.authorSeabroke, G-
dc.contributor.authorSiebert, A-
dc.contributor.authorSiviero, A-
dc.contributor.authorZwitter, T-
dc.date.accessioned2017-07-24T01:35:17Z-
dc.date.available2017-07-24T01:35:17Z-
dc.date.issued2017-
dc.identifier.citationAstronomy & Astrophysics, 2017, v. 601, article no. A59, p. 1-10-
dc.identifier.issn0004-6361-
dc.identifier.urihttp://hdl.handle.net/10722/242102-
dc.description.abstractContext. The chemical abundances of stars encode information on their place and time of origin. Stars formed together in e.g. a cluster, should present chemical homogeneity. Also disk stars influenced by the effects of the bar and the spiral arms might have distinct chemical signatures depending on the type of orbit that they follow, e.g. from the inner versus outer regions of the Milky Way. Aims. We explore the correlations between velocity and metallicity and the possible distinct chemical signatures of the velocity over-densities of the local Galactic neighbourhood. Methods. We use the large spectroscopic survey RAVE and the Geneva Copenhagen Survey. We compare the metallicity distribution of regions in the velocity plane (vR,vφ) with that of their symmetric counterparts (−vR,vφ). We expect similar metallicity distributions if there are no tracers of a sub-population (e.g. a dispersed cluster, accreted stars), if the disk of the Galaxy is axisymmetric, and if the orbital effects of the bar and the spiral arms are weak. Results. We find that the metallicity-velocity space of the solar neighbourhood is highly patterned. A large fraction of the velocity plane shows differences in the metallicity distribution when comparing symmetric vR regions. The typical differences in the median metallicity are of 0.05 dex with statistical significant of at least 95% confidence, and with values up to 0.6 dex. For stars with low azimuthal velocity vφ, the ones moving outwards. These include stars in the Hercules and Hyades moving groups and other velocity branch-like structures. For higher vφ, the stars moving inwards have higher metallicity than those moving outwards. We have also discovered a positive gradient in vφ with respect to metallicity at high metallicities, apart from the two known positive and negative gradients for the thick and thin disks. Conclusions. The most likely interpretation of the metallicity asymmetry is that it is mainly due to the orbital effects of the Galactic bar and the radial metallicity gradient of the disk. We present a simulation that supports this idea.-
dc.languageeng-
dc.publisherEDP Sciences. The Journal's web site is located at http://www.aanda.org-
dc.relation.ispartofAstronomy & Astrophysics-
dc.rightsReproduced with permission from Astronomy & Astrophysics, © ESO 2017. The original publication is available at https://doi.org/10.1051/0004-6361/201629387-
dc.subjectGalaxy: kinematics and dynamics-
dc.subjectGalaxy: structure-
dc.subjectGalaxy: disk-
dc.subjectGalaxy: evolution-
dc.subjectGalaxy: abundances-
dc.titleAsymmetric metallicity patterns in the stellar velocity space with RAVE-
dc.typeArticle-
dc.identifier.emailParker, QA: quentinp@hku.hk-
dc.identifier.authorityParker, QA=rp02017-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1051/0004-6361/201629387-
dc.identifier.scopuseid_2-s2.0-85018442206-
dc.identifier.hkuros273156-
dc.identifier.volume601-
dc.identifier.spagearticle no. A59, p. 1-
dc.identifier.epagearticle no. A59, p. 10-
dc.identifier.isiWOS:000402313500059-
dc.publisher.placeFrance-

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