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Related papers: Two substructures in the nearby stellar halo found…

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Based on the second Gaia data release (Gaia DR2) and spectroscopy from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Data, we identified 20,089 halo stars kinematically and chemically. The halo streams in the solar…

Astrophysics of Galaxies · Physics 2019-04-03 Hefan Li , Cuihua Du , Shuai Liu , Thomas Donlon , Heidi Jo Newberg

The debris from past merger events is expected and, to some extent, known to populate the stellar halo near the Sun. We aim to identify and characterise such merger debris using Gaia DR3 data supplemented by metallicity and chemical…

The local stellar halo of the Milky Way is known to contain the debris from accreted dwarf galaxies and globular clusters, in the form of stellar streams and over-densities in the space of orbital properties (e.g. integrals of motion).…

Aims. Several kinematic and chemical substructures have been recently found amongst Milky Way halo stars with retrograde motions. It is currently unclear how these various structures are related to each other. This Letter aims to shed light…

Astrophysics of Galaxies · Physics 2019-11-13 Helmer H. Koppelman , Amina Helmi , Davide Massari , Adrian M. Price-Whelan , Tjitske K. Starkenburg

We identify a halo substructure in the Tycho Gaia Astrometric Solution (TGAS) dataset, cross-matched with the RAVE-on data release. After quality cuts, the stars with large radial action ($J_R > 800$ kms$^{-1}$ kpc) are extracted. A subset…

Astrophysics of Galaxies · Physics 2018-01-25 G. C. Myeong , N. W. Evans , V. Belokurov , S. Koposov , J. L. Sanders

Using kinematic data from the Gaia Data Release 3 catalog, along with metallicity estimates robustly derived from Gaia XP spectra, we have explored the Galactic stellar halo in search of both known and potentially new substructures. By…

Astrophysics of Galaxies · Physics 2024-10-10 Haoyang Liu , Cuihua Du , Dashuang Ye , Jian Zhang , Mingji Deng

We report on the very low $\alpha$-element abundances of a group of metal-poor stars with high orbital energy and with large retrograde motion in the Milky Way halo, whose excess has been reported recently from metallicity and kinematics.…

Astrophysics of Galaxies · Physics 2019-04-17 Tadafumi Matsuno , Wako Aoki , Takuma Suda

We use the SDSS-Gaia Catalogue to identify six new pieces of halo substructure. SDSS-Gaia is an astrometric catalogue that exploits SDSS data release 9 to provide first epoch photometry for objects in the Gaia source catalogue. We use a…

Astrophysics of Galaxies · Physics 2018-01-25 G. C. Myeong , N. W. Evans , V. Belokurov , N. C. Amorisco , S. Koposov

Motivated by the vast gap between photometric and spectroscopic data volumes, there is great potential in using 5D kinematic information to identify and study substructures of the Milky Way. We identify substructures in the Galactic halo…

The hierarchical structure formation model predicts that stellar halos should form, at least partly, via mergers. If this was a predominant formation channel for the Milky Way's halo, imprints of this merger history in the form of moving…

Astrophysics of Galaxies · Physics 2017-02-01 Amina Helmi , Jovan Veljanoski , Maarten A. Breddels , Hao Tian , Laura V. Sales

We use halo dwarf stars with photometrically determined metallicities that are located within 2 kpc of the Sun to identify local halo substructure. The kinematic properties of these stars do not indicate a single, dominant radial merger…

Astrophysics of Galaxies · Physics 2022-06-29 Thomas Donlon , Heidi Jo Newberg , Bokyoung Kim , Sebastien Lepine

Recent studies show that the Milky Way stellar halo is composed of populations of different origins, shaped by multiple accretion events. To better understand the formation of the Milky Way and other spiral galaxies, we characterize the…

We explore the phase-space structure of nearby halo stars identified kinematically from Gaia DR2 data. We focus on their distribution in velocity and in "integrals of motion" space as well as on their photometric properties. Our sample of…

Astrophysics of Galaxies · Physics 2018-06-27 Helmer H. Koppelman , Amina Helmi , Jovan Veljanoski

We use the SDSS-Gaia catalogue to search for substructure in the stellar halo. The sample comprises 62\,133 halo stars with full phase space coordinates and extends out to heliocentric distances of $\sim 10$ kpc. As actions are conserved…

Astrophysics of Galaxies · Physics 2018-07-03 G. C. Myeong , N. W. Evans , V. Belokurov , J. L. Sanders , S. E. Koposov

We identify substructures of the Galactic halo using 3,003 type $ab$ RR Lyraes (RRab) with 6D position-velocity information from the SDSS, LAMOST, and Gaia EDR3. Based on the information, we define the separation of any two of the stars in…

Astrophysics of Galaxies · Physics 2022-06-01 F. Wang , H. -W. Zhang , X. -X. Xue , Y. Huang , G. -C. Liu , L. Zhang , C. -Q. Yang

Combining the LAMOST radial velocities with Gaia parallaxes and proper motions, we presented 3D Galactic space motions and the orbits of 182 single-lined hot subdwarf stars. These stars have been identified by Lei et al. (2020) in Gaia DR2…

Solar and Stellar Astrophysics · Physics 2020-07-29 Yangping Luo , Peter Nemeth , Qida Li

Combing Gaia DR2 with LAMOST DR5, we spectroscopically identified 924 hot subdwarf stars, among which 32 stars exhibit strong double-lined composite spectra. We measured the effective temperature $T_{\rm eff}$, surface gravity $\log\,g$,…

Solar and Stellar Astrophysics · Physics 2019-08-14 Yangping Luo , Péter Németh , Licai Deng , Zhanwen Han

We selected 4593 hot subdwarf candidates from the Gaia DR2 Hertzsprung-Russell (HR) diagram. By combining the sample with LAMOST DR5, we identified 294 hot subdwarf stars, including 169 sdB, 63 sdOB, 31 He-sdOB, 22 sdO, 7 He-sdO and 2…

Solar and Stellar Astrophysics · Physics 2019-07-02 Zhenxin Lei , Jingkun Zhao , Németh Péter , Gang Zhao

We construct a large halo K-giant sample by combining the positions, distances, radial velocities, and metallicities of over 13,000 LAMOST DR5 halo K giants with the Gaia DR2 proper motions, which covers a Galactocentric distance range of…

Astrophysics of Galaxies · Physics 2019-07-31 Chengqun Yang , Xiang-Xiang Xue , Jing Li , Lan Zhang , Chao Liu , Gang Zhao , Jiang Chang , Hao Tian , Chengdong Li

We applied Stars' Galactic Origin (StarGO) algorithm in 7D space (i.e., [Fe/H], [Mg/Fe], [Al/Fe], $L_{z}$, $J_{r}$, $J_{z}$, $E$) to analyze stars in the inner halo with APOGEE DR17. We identified some known substructures, including…

Astrophysics of Galaxies · Physics 2025-04-03 Zhongcheng Li , Cuihua Du , Haoyang Liu , Dashuang Ye
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