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200 papers

We map the stellar structure of the Galactic thick disk and halo by applying color-magnitude diagram (CMD) fitting to photometric data from the SEGUE survey, allowing, for the first time, a comprehensive analysis of their structure at both…

Astrophysics of Galaxies · Physics 2010-05-12 Jelte T. A. de Jong , Brian Yanny , Hans-Walter Rix , Andrew E. Dolphin , Nicolas F. Martin , Timothy C. Beers

We present mass models of the Milky Way created to fit observational constraints and to be consistent with expectations from theoretical modelling. The method used to create these models is that demonstrated in McMillan (2011), and we…

Astrophysics of Galaxies · Physics 2016-12-07 Paul J. McMillan

Previous studies have shown that disk warps can result from galaxy mergers. Recent research indicates a noticeable decline in the rotation curve (RC) of the Milky Way (MW), suggesting the need for a new low-mass model to describe its…

Astrophysics of Galaxies · Physics 2026-01-30 Mingji Deng , Cuihua Du , Jian Zhang , Haoyang Liu , Zhongbcheng Li

We present a new method for determining the Galactic gravitational potential based on forward modeling of tidal stellar streams. We use this method to test the performance of smooth and static analytic potentials in representing realistic…

Astrophysics of Galaxies · Physics 2015-06-22 Ana Bonaca , Marla Geha , Andreas H. W. Kuepper , Juerg Diemand , Kathryn V. Johnston , David W. Hogg

The hot interstellar medium traces the stellar feedback and its role in regulating the eco-system of the Galaxy. I review recent progress in understanding the medium, based largely on X-ray absorption line spectroscopy, complemented by…

Astrophysics of Galaxies · Physics 2009-08-12 Q. Daniel Wang

We analyze an adaptive mesh refinement hydrodynamic cosmological simulation of a Milky Way-sized galaxy to study the cold gas in the halo. HI observations of the Milky Way and other nearby spirals have revealed the presence of such gas in…

Astrophysics of Galaxies · Physics 2015-06-04 Ximena Fernández , M. Ryan Joung , Mary E. Putman

We present a new analysis of the observed perturbations of the HI disk of the Milky Way to infer the existence of a dark sub-halo that tidally interacted with the Milky Way disk. We examine tidal interactions between perturbing dark…

Astrophysics of Galaxies · Physics 2009-09-30 Sukanya Chakrabarti , Leo Blitz

Based on N-body simulations, we show that realistic galactic disks are subject to bending instabilities of fire-hose type when the disks are substantially self-gravitating, that is, if they contain dark matter distributed in the disk.…

Astrophysics · Physics 2007-05-23 Y. Revaz , D. Pfenniger

Abridged: We estimate the distances to ~48 million stars detected by the Sloan Digital Sky Survey and map their 3D number density distribution in 100 < D < 20 kpc range over 6,500 deg^2 of sky. The data show strong evidence for a Galaxy…

We use Gaia photometry and astrometry to estimate the vertical spatial structure of the Milky Way at the Solar radius, formally accounting for sample incompleteness (the selection function) and parallax measurement uncertainty. Our results…

Astrophysics of Galaxies · Physics 2022-02-16 Andrew Everall , Vasily Belokurov , N. Wyn Evans , Douglas Boubert , Robert J. J. Grand

We construct the first comprehensive dynamical model for the high-quality subset of stellar kinematics of the Milky Way disc, with full 6D phase-space coordinates, provided by the Gaia Data Release 2. We adopt an axisymmetric approximation…

Astrophysics of Galaxies · Physics 2020-04-24 Maria Selina Nitschai , Michele Cappellari , Nadine Neumayer

Massive galaxies at high redshift are predicted to be fed from the cosmic web by narrow, dense, cold streams. These streams penetrate supersonically through the hot medium encompassed by a stable shock near the virial radius of the…

Astrophysics of Galaxies · Physics 2016-09-20 Nir Mandelker , Dan Padnos , Avishai Dekel , Yuval Birnboim , Andreas Burkert , Mark R. Krumholz , Elad Steinberg

We propose a new model for the dark matter halo of the Milky Way that fits the properties of the stellar stream associated with the Sagittarius dwarf galaxy. Our dark halo is oblate with q_z = 0.9 for r < 10 kpc, and can be made to follow…

Astrophysics of Galaxies · Physics 2015-06-15 Carlos Vera-Ciro , Amina Helmi

We present robust constraints from the Sloan Digital Sky Survey (SDSS) on the shape and distribution of the dark matter halo within the Milky Way (MW). Using the number density distribution and kinematics of SDSS halo stars, we probe the…

A linear stability analysis of a multi-component and magnetized Galactic disk model is presented. The disk model uses the observed stratifications for the gas density and gravitational acceleration at the solar neighborhood and, in this…

Astrophysics · Physics 2009-10-31 Jongsoo Kim , Jose Franco , S. S. Hong , Alfredo Santillan , Marco A. Martos

A popular model for the circumstellar disks of Be stars is that of a geometrically thin disk with a density in the equatorial plane that drops as a power law of distance from the star. It is usually assumed that the vertical structure of…

Solar and Stellar Astrophysics · Physics 2009-07-24 T. A. A. Sigut , M. A. McGill , C. E. Jones

We report a dynamical determination of the separate contributions of disk and dark halo masses to the rotation curve of a spiral galaxy. We use fluid-dynamical models of gas flow in the barred galaxy NGC 4123 to constrain the dynamical…

Astrophysics · Physics 2008-11-26 Benjamin J. Weiner , J. A. Sellwood , T. B. Williams

We examine the evolution of the Parker instability in galactic disks using 3D numerical simulations. We consider a local Cartesian box section of a galactic disk, where gas, magnetic fields and cosmic rays are all initially in a…

Astrophysics of Galaxies · Physics 2015-12-24 Luiz Felippe S. Rodrigues , Graeme R. Sarson , Anvar Shukurov , Paul J. Bushby , Andrew Fletcher

The well-known bar instability of rotationally-supported disk galaxy models has been studied extensively since its first discovery over half a century ago. We were therefore very surprised to find cases of disks embedded in rigid halos,…

Astrophysics of Galaxies · Physics 2025-10-24 J. A. Sellwood , Victor P. Debattista , R. G. Carlberg

Cold dark matter halos are expected to be triaxial and often tilted relative to the stellar disk. Stellar streams provide a sensitive tracer of the Milky Way's halo shape, though models for the Galactic potential are typically limited to…

Astrophysics of Galaxies · Physics 2025-04-11 Jacob Nibauer , Ana Bonaca