Blind chemical tagging with DBSCAN: prospects for spectroscopic surveys

Abstract

Chemical tagging has great promise as a technique to unveil our Galaxy's history. Grouping stars based on their similar chemistry can establish details of the star formation and merger history of the Milky Way. With precise measurements of stellar chemistry, chemical tagging may be able to group together stars born from the same gas cloud, regardless of their current positions and kinematics. Successfully tagging these birth clusters requires high quality chemical space information and a good cluster-finding algorithm. To test the feasibility of chemical tagging on data from current and upcoming spectroscopic surveys, we construct a realistic set of synthetic clusters, creating both observed spectra and derived chemical abundances for each star. We use Density-Based Spatial Clustering of Applications with Noise (DBSCAN) to group stars based on their spectra or abundances; these groups are matched to input clusters and are found to be highly homogeneous and complete. The percentage of clusters with more than 10 members recovered is 40% when tagging on abundances with uncertainties achievable with current techniques. Based on our fiducial model for the Milky Way, we predict recovering over 600 clusters with at least 10 observed members and 70% membership homogeneity in a sample similar to the APOGEE survey. Tagging larger surveys like the GALAH survey and the future Milky Way Mapper in SDSS V could recover tens of thousands of clusters at high homogeneity. Access to so many unique co-eval clusters will transform how we understand the star formation history and chemical evolution of our Galaxy.

16 pages, 10 figures, accepted for publication in MNRAS

References in corpus (17)

• The Gaia mission
• The Radial Velocity Experiment (RAVE): first data release
• The GALAH Survey: Scientific Motivation
• Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars
• Disentangling the Galactic Halo with APOGEE: I. Chemical and Kinematical Investigation of Distinct Metal-Poor Populations
• Chemical Homogeneity in Collinder 261 and Implications for Chemical Tagging
• SDSS-V: Pioneering Panoptic Spectroscopy
• APOGEE Chemical Abundances of Globular Cluster Giants in the Inner Galaxy
• APOGEE Chemical Abundances of the Sagittarius Dwarf Galaxy
• Early turbulent mixing as the origin of chemical homogeneity in open star clusters
• The chemical compositions of solar twins in the open cluster M67
• The Galah Survey: Classification and diagnostics with t-SNE reduction of spectral information
• Testing the chemical tagging technique with open clusters
• Prospects for chemically tagging stars in the Galaxy
• Two Groups of Red Giants with Distinct Chemical Abundances in the Bulge Globular Cluster NGC 6553 Through the Eyes of APOGEE
• Cosmic phylogeny: reconstructing the chemical history of the solar neighbourhood with an evolutionary tree
• Re-grouping stars based on the chemical tagging technique: A case study of M67 and IC4651

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• Disentangling the origin of chemical differences using GHOST
• Tidal debris from Omega Centauri discovered with unsupervised machine learning
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• Identifying substructure associations in the Milky Way halo using chemo-kinematic tagging
• Functional Data Analysis for Extracting the Intrinsic Dimensionality of Spectra: Application to Chemical Homogeneity in the Open Cluster M67