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相关论文: On the alleged duality of the Galactic halo

200 篇论文

We re-examine recent claims of observational evidence for a dual Galactic halo in SEGUE/SDSS data, and trace them back to improper error treatment and neglect of selection effects. In particular, the detection of a vertical abundance…

星系天体物理 · 物理学 2015-06-19 Ralph Schoenrich , Martin Asplund , Luca Casagrande

Carollo et al. have recently resolved the stellar population of the Milky Way halo into at least two distinct components, an inner halo and an outer halo. This result has been criticized by Schoenrich et al., who claim that the retrograde…

We provide a set of numerical N-body simulations for studying the formation of the outer Milky Ways's stellar halo through accretion events. After simulating minor mergers of prograde and retrograde orbiting satellite halo with a Dark…

宇宙学与河外天体物理 · 物理学 2015-05-19 Giuseppe Murante , Eva Poglio , Anna Curir , Alvaro Villalobos

We use K-giant stars selected from the LAMOST DR5 to study the variation of the rotational velocity of the galactic halo at different space positions. Modelling the rotational velocity distribution with both the halo and disk components, we…

星系天体物理 · 物理学 2020-08-26 Hao Tian , Chao Liu , Yougang Wang , Yan Xu , Chengqun Yang , Bo Zhang , Xiang-Xiang Xue

We explore the stellar metallicity distribution function of the Galactic halo based on SDSS ugriz photometry. A set of stellar isochrones is calibrated using observations of several star clusters and validated by comparisons with…

The first and second moments of stellar velocities encode important information about the formation history of the Galactic halo. However, due to the lack of tangential motion and inaccurate distances of the halo stars, the velocity moments…

The halo structure at high Galactic latitudes near both the north and south poles is studied using SDSS and SuperCOSMOS data. For the south cap halo, the archive of the SuperCOSMOS photographic photometry sky survey is used. The coincident…

天体物理学 · 物理学 2008-11-26 Y. Xu , L. C. Deng , J. Y. Hu

An observer that is moving towards a high-density region sees, on average, a higher matter density and more foreground-emitting sources ahead than behind themself. Consequently, the average abundance and luminosity of objects producing…

宇宙学与河外天体物理 · 物理学 2023-10-11 Selim C. Hotinli , Elena Pierpaoli , Simone Ferraro , Kendrick Smith

With the help of Gaia DR2, we are able to obtain the full 6-D phase space information for stars from LAMOST DR5. With high precision of position, velocity, and metallicity, the rotation of the local stellar halo is presented using the K…

星系天体物理 · 物理学 2019-02-14 Hao Tian , Chao Liu , Yan Xu , Xiangxiang Xue

We use a series of high-resolution simulations of a `Milky-Way' halo coupled to semi-analytic methods to study the formation of our own Galaxy and of its stellar halo. The physical properties of our model Milky Way, as well as the age and…

天体物理学 · 物理学 2009-11-13 Gabriella De Lucia , Amina Helmi

Recently, Sun et al. (2008) published new Galactic 3D-models of magnetic fields in the disk and halo of the Milky Way and the distribution of cosmic-ray electron density by taking into account the thermal electron density model NE2001 by…

星系天体物理 · 物理学 2015-05-20 Xiaohui Sun , Wolfgang Reich

Using the stellar photometry catalogue based on the latest data release (DR4) of the Sloan Digital Sky Survey (SDSS), a study of the Galactic structure using star counts is carried out for selected areas of the sky. The sample areas are…

天体物理学 · 物理学 2009-11-11 Y. Xu , L. C. Deng , J. Y. Hu

We investigate the angular distribution of satellite galaxies in and around pairs of galaxy groups in SDSS and compare the results with the satellite distribution in pairs of dark matter halos by constructing mock catalogs that account for…

星系天体物理 · 物理学 2025-09-01 Yanhan Guo , Qinglin Ma , Cheng Li

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…

We have used RR Lyrae and Blue HB stars as tracers of the old Galactic halo, in order to study the halo structure and the galactic rotation as a function of height above the plane. Our sample includes 40 RR Lyrae and 80 BHB stars that are…

天体物理学 · 物理学 2007-05-23 T. D. Kinman , A. Bragaglia , C. Cacciari , A. Buzzoni , A. Spagna

High velocity gas that does not conform to Galactic rotation is observed throughout the Galaxy's halo. One component of this gas, HI high velocity clouds (HVCs), have attracted attention since their discovery in the 1960s and remain…

星系天体物理 · 物理学 2017-08-24 Asger Grønnow , Thor Tepper-García , Joss Bland-Hawthorn , Naomi McClure-Griffiths

The shape of the dark matter (DM) halo is key to understanding the hierarchical formation of the Galaxy. Despite extensive efforts in recent decades, however, its shape remains a matter of debate, with suggestions ranging from strongly…

We have measured the amount of kinematic substructure in the Galactic halo using the final data set from the Spaghetti project, a pencil-beam high latitude sky survey. Our sample contains 101 photometrically selected and spectroscopically…

The rotation of the galactic halos is a fascinating topic which is still waiting to be addressed. Planck data has shown the existence of a temperature asymmetry towards the halo of several nearby galaxies, such as M31, NGC 5128, M33, M81,…

星系天体物理 · 物理学 2021-11-17 Noraiz Tahir , Francesco De Paolis , Asghar Qadir , Achille A. Nucita

Although the stellar halo accounts for just ~1% of the total stellar mass of the Milky Way, the kinematics of halo stars encode valuable information about the origins and evolution of our Galaxy. It has been shown that the high transverse…

星系天体物理 · 物理学 2020-01-15 João A. S. Amarante , Martin C. Smith , Corrado Boeche
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