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Related papers: Radial halo substructure in harmony with the Galac…

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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…

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

In a framework where galaxies form hierarchically, extended stellar haloes are predicted to be an ubiquitous feature around Milky Way-like galaxies and to consist mainly of the shredded stellar component of smaller galactic systems. The…

Astrophysics of Galaxies · Physics 2017-12-20 G. Battaglia , P. North , P. Jablonka , M. Shetrone , D. Minniti , M. Díaz , E. Starkenburg , M. Savoy

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

Hypervelocity stars (HVSs) travel from the Galactic Centre across the dark matter halo of the Milky Way, where they are observed with velocities in excess of the Galactic escape speed. Because of their quasi-radial trajectories, they…

Astrophysics of Galaxies · Physics 2019-06-14 O. Contigiani , E. M. Rossi , T. Marchetti

Recent work indicates that the nearby Galactic halo is dominated by the debris from a major accretion event. We confirm that result from an analysis of APOGEE-DR14 element abundances and $\textit{Gaia}$-DR2 kinematics of halo stars. We show…

We analyse the positions of RR Lyrae stars in the central region of the Milky Way. In addition to the overall bar shape detected previously, we find evidence for a peanut shaped structure, in form of overdensities near $\ell=-2$ deg and $1$…

Astrophysics of Galaxies · Physics 2021-11-24 Marcin Semczuk , Walter Dehnen , Ralph Schoenrich , E. Athanassoula

We measure the three components of velocity dispersion, $\sigma_{R},\sigma_{\theta},\sigma_{\phi}$, for stars within 6 < R < 30 kpc of the Milky Way using a new radial velocity sample from the MMT telescope. We combine our measurements with…

Astrophysics of Galaxies · Physics 2015-11-11 Charles King , Warren R. Brown , Margaret J. Geller , Scott J. Kenyon

Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most…

Astrophysics · Physics 2009-06-23 Amina Helmi

We explore the properties of Milky Way subhalos in self-interacting dark matter models for moderate cross sections of 1 to 5 cm$^2$g$^{-1}$ using high-resolution zoom-in N-body simulations. We include the gravitational potential of a…

Astrophysics of Galaxies · Physics 2022-11-30 Maya Silverman , James S. Bullock , Manoj Kaplinghat , Victor H. Robles , Mauro Valli

We constrain the shape of the Milky Way's halo by dynamical modeling of the observed phase-space tracks of the Pal 5 and GD-1 tidal streams. We find that the only information about the potential gleaned from the tracks of these streams are…

Astrophysics of Galaxies · Physics 2017-02-10 Jo Bovy , Anita Bahmanyar , Tobias K. Fritz , Nitya Kallivayalil

The formation and structure of the Milky Way has a fundamental role in our understanding of the universe and its evolution, and thanks to the Gaia mission and large spectroscopic surveys, we live an exceptional moment of data availability,…

Astrophysics of Galaxies · Physics 2024-05-08 Elvis Cantelli , Ramachrisna Teixeira

Understanding radial migration is a crucial point to build relevant chemical and dynamical evolution models of the Milky Way disk. In this paper, we analyze a high-resolution N-body simulation of a Milky Way-type galaxy to study the role…

Astrophysics of Galaxies · Physics 2020-07-01 S. Khoperskov , P. Di Matteo , M. Haywood , A. Gomez , O. N. Snaith

The Milky Way hosts a hot ($\approx 2 \times 10^6$ K), diffuse, gaseous halo based on detections of z = 0 OVII and OVIII absorption lines in quasar spectra and emission lines in blank-sky spectra. Here we improve constraints on the…

Astrophysics of Galaxies · Physics 2015-06-23 Matthew J. Miller , Joel N. Bregman

We have used data from the Sloan Digital Sky Survey (SDSS) Data Release 5 to explore the overall structure and substructure of the stellar halo of the Milky Way using about 4 million color-selected main sequence turn-off stars. We fit…

A strong bar rotating within a massive halo should lose angular momentum to the halo through dynamical friction, as predicted by Weinberg. We have conducted fully self-consistent, numerical simulations of barred galaxy models with a live…

Astrophysics · Physics 2015-06-24 J. A. Sellwood , Victor P. Debattista

A simple model for the Milky Way halo is presented. It has a flat rotation curve in the inner regions, but the density falls off sharply beyond an outer edge. This truncated, flat rotation curve (TF) model possesses a rich family of simple…

Astrophysics · Physics 2008-11-26 M. I. Wilkinson , N. W. Evans

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

The study of binary stars in the Galactic halo provides crucial insights into the dynamical history and formation processes of the Milky Way. In this work, we aim to investigate the binary fraction in a sample of accreted and in-situ halo…

Astrophysics of Galaxies · Physics 2024-11-14 Dolev Bashi , Vasily Belokurov , Simon Hodgkin

The inner Galactic halo is a complex graveyard of the Milky Way's earliest accretion events, where severe orbital phase-mixing challenges traditional dynamical stream-finding techniques. We present a purely data-driven, 12-dimensional…

Astrophysics of Galaxies · Physics 2026-05-25 Furkan Akbaba , Olcay Plevne