Journal article
The GALAH survey: chemical tagging of star clusters and new members in the Pleiades
Monthly notices of the Royal Astronomical Society, Vol.473(4), pp.4612-4633
02/01/2018
DOI: 10.1093/mnras/stx2637
Abstract
The technique of chemical tagging uses the elemental abundances of stellar atmospheres to 'reconstruct' chemically homogeneous star clusters that have long since dispersed. The GALAH spectroscopic survey - which aims to observe one million stars using the Anglo-Australian Telescope - allows us to measure up to 30 elements or dimensions in the stellar chemical abundance space, many of which are not independent. How to find clustering reliably in a noisy high-dimensional space is a difficult problem that remains largely unsolved. Here, we explore t-distributed stochastic neighbour embedding (t-SNE) - which identifies an optimal mapping of a high-dimensional space into fewer dimensions - whilst conserving the original clustering information. Typically, the projection is made to a 2D space to aid recognition of clusters by eye. We show that this method is a reliable tool for chemical tagging because it can: (i) resolve clustering in chemical space alone, (ii) recover known open and globular clusters with high efficiency and low contamination, and (iii) relate field stars to known clusters. t-SNE also provides a useful visualization of a high-dimensional space. We demonstrate the method on a data set of 13 abundances measured in the spectra of 187 000 stars by the GALAH survey. We recover seven of the nine observed clusters (six globular and three open clusters) in chemical space with minimal contamination from field stars and low numbers of outliers. With chemical tagging, we also identify two Pleiades supercluster members (which we confirm kinematically), one as far as 6 degrees-one tidal radius away from the cluster centre.
Details
- Title: Subtitle
- The GALAH survey: chemical tagging of star clusters and new members in the Pleiades
- Creators
- Janez Kos - The University of SydneyJoss Bland-Hawthorn - The University of SydneyKen Freeman - Australian National UniversitySven Buder - Max Planck Institute for AstronomyGregor Traven - University of LjubljanaGayandhi M. De Silva - The University of SydneySanjib Sharma - The University of SydneyMartin Asplund - Australian National UniversityLy Duong - Australian National UniversityJane Lin - Australian National UniversityKarin Lind - Uppsala UniversitySarah Martell - UNSW SydneyJeffrey D. Simpson - Macquarie UniversityDennis Stello - The University of SydneyDaniel B. Zucker - Macquarie UniversityTomaz Zwitter - University of LjubljanaBorja Anguiano - University of VirginiaGary Da Costa - Australian National UniversityValentina D'Orazi - Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, ItalyJonathan Horner - University of Southern QueenslandPrajwal R. Kafle - International Centre for Radio Astronomy ResearchGeraint Lewis - The University of SydneyUlisse Munari - National Institute for AstrophysicsDavid M. Nataf - Johns Hopkins UniversityMelissa Ness - Max Planck Institute for AstronomyWarren Reid - Western Sydney UniversityKatie Schlesinger - Australian National UniversityYuan-Sen Ting - Australian National UniversityRosemary Wyse - Johns Hopkins University
- Resource Type
- Journal article
- Publication Details
- Monthly notices of the Royal Astronomical Society, Vol.473(4), pp.4612-4633
- DOI
- 10.1093/mnras/stx2637
- ISSN
- 0035-8711
- eISSN
- 1365-2966
- Publisher
- Oxford Univ Press
- Number of pages
- 22
- Grant note
- Allan C. and Dorothy H. Davis Fellowship DE140100598; FT110100793; DP150104667 / Australian Research Council P1-0188 / Slovenian Research Agency; Slovenian Research Agency - Slovenia
- Language
- English
- Date published
- 02/01/2018
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984701734302771
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