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Recently, radial velocities have been measured for a large sample of M giants from the 2MASS catalog, selected to be part of the Sgr dwarf leading and trailing streams. Here we present a comparison of their kinematics to models of the Sgr…

天体物理学 · 物理学 2009-11-10 Amina Helmi

Models of the Sagittarius Stream have consistently found that the Milky Way disc is oriented such that its short axis is along the intermediate axis of the triaxial dark matter halo. We attempt to build models of disc galaxies in such an…

星系天体物理 · 物理学 2015-06-12 Victor P. Debattista , Rok Roskar , Monica Valluri , Thomas Quinn , Ben Moore , James Wadsley

Dwarf galaxies populating the Galactic halo are assumed to host the largest fractions of dark matter, as calculated from their velocity dispersions. Their major axes are preferentially aligned with the Vast Polar Structure (VPOS) that is…

The outer disk of the Milky Way Galaxy is warped and flared. Several mechanisms have been proposed to explain these phenomena, but none have quantitatively reproduced both features. Recent work has demonstrated that the Galactic stellar…

星系天体物理 · 物理学 2023-09-15 Jiwon Jesse Han , Charlie Conroy , Lars Hernquist

We assemble a catalogue of candidate Sagittarius stream members with 5d and 6d phase-space information, using astrometric data from Gaia DR2, distances estimated from RR Lyrae stars, and line-of-sight velocities from various spectroscopic…

星系天体物理 · 物理学 2021-02-22 Eugene Vasiliev , Vasily Belokurov , Denis Erkal

Using a variety of stellar tracers -- blue horizontal branch stars, main-sequence turn-off stars and red giants -- we follow the path of the Sagittarius (Sgr) stream across the sky in Sloan Digital Sky Survey data. Our study presents new…

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…

星系天体物理 · 物理学 2025-04-11 Jacob Nibauer , Ana Bonaca

We study how structural properties of globular clusters and dwarf galaxies are linked to their orbits in the Milky Way halo. From the inner to the outer halo, orbital energy increases and stellar-systems gradually move out of internal…

Stellar streams result from the tidal disruption of satellites and star clusters as they orbit a host galaxy, and can be very sensitive probes of the gravitational potential of the host system. We select and study narrow stellar streams…

星系天体物理 · 物理学 2017-03-08 Robyn E. Sanderson , Johanna Hartke , Amina Helmi

Stellar streams provide unique probes of galactic potentials, with the longer streams normally providing the cleaner measurements. In this paper, we show an example of a short tidal stream that is particularly sensitive to the shape of the…

星系天体物理 · 物理学 2015-06-04 H. Lux , J. I. Read , G. Lake , K. V. Johnston

The infall of the Sagittarius (Sgr) Dwarf Spheroidal Galaxy in the Milky Way halo is an unique opportunity to understand how the different components of a dwarf galaxy could be tidally removed. In this work, we reconstruct the Sgr core…

星系天体物理 · 物理学 2022-11-30 Hai-Feng Wang , Francois Hammer , Yan-Bin Yang , Jian-Ling Wang

The Sagittarius dwarf spheroidal (Sgr dSph) galaxy provides one of the most convincing examples of tidal interaction between satellite galaxies and the Milky Way (MW). The main body of the dwarf was recently demonstrated to have an…

星系天体物理 · 物理学 2024-07-03 Ewa L. Lokas

An all high-latitude sky survey for cool carbon giant stars in the Galactic halo has revealed 75 such stars, of which the majority are new detections. Of these, more than half are clustered on a Great Circle on the sky which intersects the…

天体物理学 · 物理学 2009-10-31 Rodrigo Ibata , Geraint F. Lewis , Michael Irwin , Edward Totten , Thomas Quinn

Using N-body simulations we study the tidal evolution of initially disky dwarf galaxies orbiting a Milky Way-like host, a process known to lead to the formation of dwarf spheroidal galaxies. We focus on the effect of the orientation of the…

星系天体物理 · 物理学 2015-10-12 Ewa L. Lokas , Marcin Semczuk , Grzegorz Gajda , Elena D'Onghia

We measure the spatial density of F turnoff stars in the Sagittarius dwarf tidal stream, from Sloan Digital Sky Survey (SDSS) data, using statistical photometric parallax. We find a set of continuous, consistent parameters that describe the…

Our situation as occupants of the Milky Way (MW) Galaxy, bombarded by the Sagittarius dwarf galaxy, provides an intimate view of physical processes that can lead to the dynamical heating of a galactic disc. While this evolution is…

Stellar streams are sensitive tracers of the gravitational potential, which is typically assumed to be static in the inner Galaxy. However, massive mergers like Gaia-Sausage-Enceladus can impart torques on the stellar disk of the Milky Way…

星系天体物理 · 物理学 2023-12-18 Jacob Nibauer , Ana Bonaca , Mariangela Lisanti , Denis Erkal , Zoe Hastings

Satellites orbiting disc galaxies can induce phase space features such as spirality, vertical heating and phase-mixing in their discs. Such features have also been observed in our own Galaxy, but the complexity of the Milky Way disc has…

星系天体物理 · 物理学 2020-03-31 Tomás Ruiz-Lara , Carme Gallart , Edouard J. Bernard , Santi Cassisi

We present a mass model for the Milky Way, which is fit to observations of the Sagittarius stream together with constraints derived from a wide range of photometric and kinematic data. The model comprises a S\'{e}rsic bulge, an exponential…

星系天体物理 · 物理学 2015-06-11 N. Deg , Lawrence Widrow

The cold dark matter picture predicts an abundance of substructure within the Galactic halo. However, most substructures host no stars and can only be detected indirectly. Stellar streams present a promising probe of this dark substructure.…

星系天体物理 · 物理学 2022-05-18 M. Sten Delos , Fabian Schmidt