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相关论文: Mapping Milky Way Halo Substructure using Stars in…

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We present a complete spectroscopic survey of 2414 2MASS-selected blue horizontal branch (BHB) candidates selected over 4300 deg^2 of the sky. We identify 655 BHB stars in this non-kinematically selected sample. We calculate the luminosity…

We study the Milky Way region Z<3.0 kpc, where the thick disk and inner halo overlap, by using the kinematics of local blue horizontal branch (BHB) stars (within 1 kpc) and new samples of BHB stars and A-type stars from the Century Survey.…

天体物理学 · 物理学 2009-11-13 T. D. Kinman , Heather L. Morrison , Warren R. Brown

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…

星系天体物理 · 物理学 2015-05-27 A. J. Deason , V. Belokurov , N. W. Evans

The distribution of Milky Way halo blue horizontal-branch (BHB) stars is examined using action-based extended distribution functions (EDFs) that describe the locations of stars in phase space, metallicity, and age. The parameters of the…

星系天体物理 · 物理学 2016-08-29 Payel Das , Angus Williams , James Binney

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…

星系天体物理 · 物理学 2020-02-18 Lachlan Lancaster , Sergey E. Koposov , Vasily Belokurov , N. Wyn Evans , Alis J. Deason

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…

We discuss a 175 deg^2 spectroscopic survey for blue horizontal branch (BHB) stars in the Galactic halo. We use the Two Micron All Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS) to select BHB candidates, and find that the 2MASS…

Halo samples that have no kinematic bias have been successfully isolated by photometric observations. We show that the near-UV (NUV) magnitude of the GALEX All-Sky Survey can be used, together with Johnson BV magnitudes in a (NUV-V)_0 vs.…

天体物理学 · 物理学 2009-11-13 T. D. Kinman , S. Salim , L. Clewley

We present 2-degree field spectroscopic observations of a sample of 96 A-type stars selected from the Sloan Digital Sky Survey Data Release 3 (SDSS DR3). Our aim is to identify blue horizontal branch (BHB) stars in order to measure the…

天体物理学 · 物理学 2009-11-11 L. Clewley , Matt J. Jarvis

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…

The stars within our Galactic halo presents a snapshot of its ongoing growth and evolution, probing galaxy formation directly. Here, we present our first analysis of the stellar halo from detailed maps of Blue Horizontal Branch (BHB) stars…

星系天体物理 · 物理学 2018-08-01 Zhen Wan , Prajwal R. Kafle , Geraint F. Lewis , Dougal Mackey , Sanjib Sharma , Rodrigo A. Ibata

The formation of the Milky Way stellar halo is thought to be the result of merging and accretion of building blocks such as dwarf galaxies and massive globular clusters. Recently, Deason et al. (2015) suggested that the Milky Way outer halo…

星系天体物理 · 物理学 2015-12-02 Chul Chung , Young-Wook Lee , Mario Pasquato

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…

星系天体物理 · 物理学 2015-06-12 Kohei Hattori , Yuzuru Yoshii , Timothy C. Beers , Daniela Carollo , Young Sun Lee

We use Legacy Survey photometric data to probe the stellar halo in multiple directions of the sky using a probabilistic methodology to identify Blue Horizontal Branch (BHB) stars. The measured average radial density profile follows a double…

星系天体物理 · 物理学 2024-10-09 João A. S. Amarante , Sergey E. Koposov , Chervin F. P. Laporte

We present an updated sample of blue horizontal-branch (BHB) stars selected from the photometric and spectroscopic data from Sloan Digital Sky Survey and its associated project Sloan Extension for Galactic Understanding and Exploration…

SCUSS is a u-band photometric survey covering about 4000 square degree of the South Galactic Cap, reaching depths of up to 23 mag. By extending around 1.5 mag deeper than SDSS single-epoch u data, SCUSS is able to probe much a larger volume…

We attempt to constrain the shape of M31's inner stellar halo by tracing the surface density of blue horizontal branch (BHB) stars at galactocentric distances ranging from 2 kpc to 35 kpc. Our measurements make use of resolved stellar…

We present a study of Far Ultraviolet (FUV) bright horizontal branch (HB) stars to understand the peculiarities seen in the HB sequence of the Globular Cluster NGC 1851, using ground and space based multi-wavelength data. Optical and UV…

太阳与恒星天体物理 · 物理学 2020-12-16 Gaurav Singh , Snehalata Sahu , Annapurni Subramaniam , R. K. S. Yadav

We exploit the exquisite, deep Hyper Suprime-Cam (HSC) imaging data to probe the Galactic halo out to 200 kpc. Using the ~100 square degree, multi-band photometry of the first HSC Wide survey data release, we identify blue horizontal branch…

星系天体物理 · 物理学 2018-01-31 Alis J. Deason , Vasily Belokurov , Sergey E. Koposov

We present an analysis of the relative age distribution of the Milky Way halo, based on samples of blue horizontal-branch (BHB) stars obtained from the Panoramic Survey Telescope and Rapid Response System and \textit{Galaxy Evolution…