Nearby stellar substructures in the Galactic halo from DESI Milky Way Survey Year 1 Data Release
Nearby stellar substructures in the Galactic halo from DESI Milky Way Survey Year 1 Data Release
We report five nearby ($d_{\mathrm{helio}} < 5$ kpc) stellar substructures in the Galactic halo from a subset of 138,661 stars in the Dark Energy Spectroscopic Instrument (DESI) Milky Way Survey Year 1 Data Release. With an unsupervised clustering algorithm, HDBSCAN*, these substructures are independently identified in Integrals of Motion ($E_{\mathrm{tot}}$, $L_{\mathrm z}$, $\log{J_r}$, $\log{J_z}$) space and Galactocentric cylindrical velocity space ($V_{R}$, $V_{\phi}$, $V_{z}$). We associate all identified clusters with known nearby substructures (Helmi streams, M18-Cand10/MMH-1, Sequoia, Antaeus, and ED-2) previously reported in various studies. With metallicities precisely measured by DESI, we confirm that the Helmi streams, M18-Cand10, and ED-2 are chemically distinct from local halo stars. We have characterised the chemodynamic properties of each dynamic group, including their metallicity dispersions, to associate them with their progenitor types (globular cluster or dwarf galaxy). Our approach for searching substructures with HDBSCAN* reliably detects real substructures in the Galactic halo, suggesting that applying the same method can lead to the discovery of new substructures in future DESI data. With more stars from future DESI data releases and improved astrometry from the upcoming Gaia Data Release 4, we will have a more detailed blueprint of the Galactic halo, offering a significant improvement in our understanding of the formation and evolutionary history of the Milky Way Galaxy.
Amanda Bystr?m、Jaime Forero-Romero、Todd Claybaugh、Hu Zou、Bokyoung Kim、Sergey E. Koposov、Axel de la Macorra、Oleg Y. Gnedin、Satya Gontcho A Gontcho、Gaston Gutierrez、Julien Guy、Klaus Honscheid、Robert Kehoe、Namitha Kizhuprakkat、Martin Landriau、Laurent Le Guillou、Michael Levi、Gustavo E. Medina、Aaron Meisner、Ramon Miquel、Ting S. Li、Sophia Lilleengen、Andrew P. Cooper、Andreia Carrillo、Monica Valluri、Alexander H. Riley、Jiwon Jesse Han、Jessica Nicole Aguilar、Steven Ahlen、Leandro Beraldo e Silva、Davide Bianchi、David Brooks、John Moustakas、Claire Poppett、Francisco Prada、Graziano Rossi、Eusebio Sánchez、Michael Schubnell、Ray Sharples、David Sprayberry、José Arturo Trelles Hernández、Benjamin Alan Weaver、Shaun Cole、Kyle Dawson
天文学
Amanda Bystr?m,Jaime Forero-Romero,Todd Claybaugh,Hu Zou,Bokyoung Kim,Sergey E. Koposov,Axel de la Macorra,Oleg Y. Gnedin,Satya Gontcho A Gontcho,Gaston Gutierrez,Julien Guy,Klaus Honscheid,Robert Kehoe,Namitha Kizhuprakkat,Martin Landriau,Laurent Le Guillou,Michael Levi,Gustavo E. Medina,Aaron Meisner,Ramon Miquel,Ting S. Li,Sophia Lilleengen,Andrew P. Cooper,Andreia Carrillo,Monica Valluri,Alexander H. Riley,Jiwon Jesse Han,Jessica Nicole Aguilar,Steven Ahlen,Leandro Beraldo e Silva,Davide Bianchi,David Brooks,John Moustakas,Claire Poppett,Francisco Prada,Graziano Rossi,Eusebio Sánchez,Michael Schubnell,Ray Sharples,David Sprayberry,José Arturo Trelles Hernández,Benjamin Alan Weaver,Shaun Cole,Kyle Dawson.Nearby stellar substructures in the Galactic halo from DESI Milky Way Survey Year 1 Data Release[EB/OL].(2025-04-28)[2025-05-28].https://arxiv.org/abs/2504.20327.点此复制
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