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Related papers: Quantifying Kinematic Substructure in the Milky Wa…

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We introduce a new maximum likelihood method to model the density profile of Blue Horizontal Branch and Blue Straggler stars and apply it to the Sloan Digital Sky Survey Data Release 8 (DR8) photometric catalogue. There are a large number…

Astrophysics of Galaxies · Physics 2015-05-27 A. J. Deason , V. Belokurov , N. W. Evans

We present a new, high-resolution chronographic (age) map of the Milky Way's halo, based on the inferred ages of ~130,000 field blue horizontal-branch (BHB) stars with photometry from the Sloan Digital Sky Survey. Our map exhibits a strong…

Astrophysics of Galaxies · Physics 2016-09-08 D. Carollo , T. C. Beers , V. M. Placco , R. M. Santucci , P. Denissenkov , P. B. Tissera , G. Lentner , S. Rossi , Y. S. Lee , J. Tumlinson

We have analyzed the catalog of 2106 non-kinematically selected metal poor stars in the solar neighborhood published by Beers et al. (2000), with the goal of quantifying the amount of substructure in the motions of the fastest halo stars.…

Astrophysics · Physics 2007-05-23 P. ReFiorentin , A. Helmi , M. G. Lattanzi , A. Spagna

We present a spectroscopic sample of 910 distant halo stars from the Hypervelocity Star survey from which we derive the velocity dispersion profile of the Milky Way halo. The sample is a mix of 74% evolved horizontal branch stars and 26%…

Astrophysics of Galaxies · Physics 2010-07-22 Warren R. Brown , Margaret J. Geller , Scott J. Kenyon , Antonaldo Diaferio

Blue Horizontal Branch (BHB) stars, excellent distant tracers for probing the Milky Way's halo density profile, are distinguished in the $(g-r)_0$ vs $(i-z)_0$ color space from another class of stars, blue straggler stars (BSs). We develop…

We selected BHB stars based on synthetic photometry and stellar atmosphere parameters inferred from Gaia Bp/Rp spectra. We generated the synthetic SDSS broad-band $ugr$ and Pristine narrow-band CaHK magnitudes from Gaia Bp/Rp data. A…

We construct a new sample of ~1700 solar neighbourhood halo subdwarfs from the Sloan Digital Sky Survey, selected using a reduced proper motion diagram. Radial velocities come from the SDSS spectra and proper motions from the light-motion…

Astrophysics of Galaxies · Physics 2009-11-19 M. C. Smith , N. W. Evans , V. Belokurov , P. C. Hewett , D. M. Bramich , G. Gilmore , M. J. Irwin , S. Vidrih , D. B. Zucker

Using the data from the Sloan Digital Sky Survey and the Gaia satellite, we assemble a pure sample of $\sim$3000 Blue Horizontal Branch (BHB) stars with 7-D information, including positions, velocities and metallicities. We demonstrate…

Astrophysics of Galaxies · Physics 2020-02-18 Lachlan Lancaster , Sergey E. Koposov , Vasily Belokurov , N. Wyn Evans , Alis J. Deason

We construct a new catalog of the blue horizontal-branch (BHB) stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR5 dataset, which contains 5355+81 BHB stars at high Galactic latitude (($|Glat|>20^{\circ}$).…

Astrophysics of Galaxies · Physics 2023-11-29 Jie Ju , Wenyuan Cui , Zhenyan Huo , Chao liu , Xiangxiang Xue , Jiaming Liu , Shuai Feng , Mingxu Sun , Linlin Li

We build a sample of distant (D > 80 kpc) stellar halo stars with measured radial velocities. Faint ($20 < g <22$) candidate blue horizontal branch (BHB) stars were selected using the deep, but wide, multi-epoch Sloan Digital Sky Survey…

We describe a major survey of the Milky Way halo designed to test for kinematic substructure caused by destruction of accreted satellites. We use the Washington photometric system to identify halo stars efficiently for spectroscopic…

Red horizontal-branch (RHB) stars have been selected from the HIPPARCOS catalogue to investigate their kinematics and spatial distribution. HIPPARCOS parallaxes, literature radial velocities and HIPPARCOS proper motions, together with…

Astrophysics · Physics 2009-11-10 T. A. Kaempf , K. S. de Boer , M. Altmann

The orbital motions of halo stars in the Milky Way reflect the orbital motions of the progenitor systems in which they formed, making it possible to trace the mass-assembly history of the Galaxy. Direct measurement of three-dimensional…

Astrophysics of Galaxies · Physics 2015-06-12 Kohei Hattori , Yuzuru Yoshii , Timothy C. Beers , Daniela Carollo , Young Sun Lee

Blue horizontal-branch (BHB) stars are old, low-mass, metal-poor stars that serve as important tracers of the Galactic halo structure, kinematics, and evolution.Understanding their binary properties provides key insights into their…

Solar and Stellar Astrophysics · Physics 2025-10-01 Yanjun Guo , Kun Chen , Zhenwei Li , Jie Ju , Chao Liu , Xiangxiang Xue , Matti Dorsch , Zhanwen Han , XueFei Chen

We characterize the population of blue horizontal-branch (BHB) stars in the bulge-halo transition region of the Milky Way using the VISTA Variables in the V\'ia L\'actea (VVV) ESO Public Survey data. The selection of BHB stars is made using…

Solar and Stellar Astrophysics · Physics 2019-03-06 Katherine Montenegro , Dante Minniti , Javier Alonso-García , Maren Hempel , Roberto K. Saito , Timothy C. Beers , David Brown

We test the long-term kinematical stability of a Galactic stellar halo model, due to Kafle, et al. (2012), who study the kinematics of approximately 5000 blue horizontal branch (BHB) stars in the Sloan Digital Sky Survey (SDSS). The…

Astrophysics of Galaxies · Physics 2015-07-03 Sarah A. Bird , Chris Flynn

Blue horizontal-branch (BHB) stars are evolved low-mass objects that have completed their core hydrogen burning main-sequence (MS) stage and have lost significant mass during the red giant phase culminating in the helium flash. We determine…

Space motions are given for 38 RR Lyrae (RRL) stars and 79 blue horizontal branch (BHB) stars in a ~200 deg2 area around the North Galactic Pole (NGP) using a homogeneous distance scale consistent with (m-M)0=18.52 for the LMC. The…

Astrophysics · Physics 2008-11-26 T. D. Kinman , C. Cacciari , A. Bragaglia , A. Buzzoni , A. Spagna

We use 2MASS photometry to select blue horizontal branch (BHB) candidates covering the sky |b|>15 deg. A 12.5<J<15.5 sample of BHB stars traces the thick disk and inner halo to d<9 kpc, with a density comparable to that of M giant stars. We…

Astrophysics · Physics 2015-06-24 Warren R. Brown , M. J. Geller , S. J. Kenyon , T. C. Beers , M. J. Kurtz , J. B. Roll