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Related papers: Mapping Dark Matter with Extragalactic Stellar Str…

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The Orphan Stream is one of the most prominent tidal streams in the Galactic halo. Using data on red giants, RR Lyrae, and horizontal branch stars from Gaia and other surveys, we determine the proper motion of the Orphan Stream over a path…

Astrophysics of Galaxies · Physics 2019-04-10 Mark A. Fardal , Roeland P. van der Marel , Sangmo Tony Sohn , Andres del Pino Molina

The shape of the Galactic dark halo can, in principle, be inferred through modelling of stellar tidal streams in the Milky Way halo. The brightest and the longest of these, the Sagittarius stream, reaches out to large Galactocentric…

Astrophysics of Galaxies · Physics 2016-02-18 S. L. J. Gibbons , V. Belokurov , D. Erkal , N. W. Evans

We investigate the formation and evolution of axion streams generated by the tidal disruption of axion miniclusters through stellar encounters in the Milky Way halo. Combining a large-scale Monte Carlo treatment of repeated stellar flybys…

Astrophysics of Galaxies · Physics 2026-05-28 Luca Visinelli , Momchil Naydenov

The Milky Way halo is one of the few galactic haloes that provides a unique insight into galaxy formation by resolved stellar populations. Here, we present a catalogue of $\sim$47 million halo stars selected independent of parallax and…

Data from the Gaia satellite show that the solar neighbourhood of the Milky Way's stellar halo is imprinted with substructure from several accretion events. Evidence of these events is found in "the Shards", stars clustering with high…

Astrophysics of Galaxies · Physics 2020-01-15 Ciaran A. J. O'Hare , N. Wyn Evans , Christopher McCabe , GyuChul Myeong , Vasily Belokurov

We explore how diffuse stellar light and globular clusters (GCs) can be used to trace the matter distribution of their host halo using an observational methodology. For this, we use 117 simulated dark matter (DM) haloes from the $(34.4~\rm…

Velocity dispersion ($\sigma$) in stellar streams from globular clusters (GCs) is sensitive to heating by Galactic substructure, including dark matter (DM) subhalos. Recent studies have compared $\sigma$ in observed and modeled streams to…

Astrophysics of Galaxies · Physics 2025-11-20 Newlin C. Weatherford , Ana Bonaca

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…

Astrophysics · Physics 2009-10-31 Rodrigo Ibata , Geraint F. Lewis , Michael Irwin , Edward Totten , Thomas Quinn

We present stellar radial velocity data for the Draco dwarf spheroidal galaxy obtained using the AF2/WYFFOS instrument combination on the William Herschel Telescope. Our dataset consists of 186 member stars, 159 of which have good quality…

Astrophysics · Physics 2009-11-07 J. T. Kleyna , M. I. Wilkinson , N. W. Evans , G. Gilmore

In addition to a smooth component of WIMP dark matter in galaxies, there may be streams of material; the effects of WIMP streams on direct detection experiments is examined in this paper. The contribution to the count rate due to the stream…

Astrophysics · Physics 2008-11-26 Chris Savage , Katherine Freese , Paolo Gondolo

The satellite system of Centaurus A presents a curious cosmological puzzle: while the global population is consistent with theoretical expectations, its inner regions (d<150 kpc) exhibit a deficit of luminous satellite galaxies. Using the…

In direct searches of dark matter, multi-scatter signatures are now being sought to probe scattering cross sections that are large enough to make the detector optically thick to incident particles. We provide some significant updates to the…

High Energy Physics - Phenomenology · Physics 2024-10-30 Harsh Aggarwal , Nirmal Raj

Dark matter sub-halos that pass near or through a thin tidal star stream locally increase its velocity dispersion. Subsequent orbital evolution further increases the velocity dispersion and stream width, lowering the surface density of a…

Astrophysics of Galaxies · Physics 2023-07-06 Raymond G. Carlberg , Hayley Agler

The phase-space structure of our Galaxy holds the key to understand and reconstruct its formation. The Lambda-CDM model predicts a richly structured phase-space distribution of dark matter and (halo) stars, consisting of streams of…

Astrophysics of Galaxies · Physics 2015-05-19 Rainer J. Klement

We use N-body simulations to explore the origin and a plausible orbit for the Orphan Stream, one of the faintest substructures discovered so far in the outer halo of our Galaxy. We are able to reproduce its position, velocity and distance…

The phase space of stellar streams is proposed to detect dark substructure in the Milky Way through the perturbations created by passing subhalos - and thus is a powerful test of the cold dark matter paradigm and its alternatives. Using…

Astrophysics of Galaxies · Physics 2025-07-16 Peter Xiangyuan Ma , Keir K. Rogers , Ting S. Li , Renée Hložek , Jeremy Webb , Ruth Huang , Julian Meunier

Terrestrial searches for the conversion of dark matter axions or axion-like particles into photons inside magnetic fields are sensitive to the phase space structure of the local Milky Way halo. We simulate signals in a hypothetical future…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-29 Ciaran A. J. O'Hare , Anne M. Green

We report the discovery of a statistically significant hardening in the Fermi-LAT $\gamma$-ray spectrum of Centaurus A's core, with the spectral index hardening from $\Gamma_{1}=2.73 \pm 0.02$ to $\Gamma_{1}=2.29 \pm 0.07$ at a break energy…

High Energy Astrophysical Phenomena · Physics 2017-11-16 Anthony M. Brown , Celine Bœhm , Jamie Graham , Thomas Lacroix , Paula Chadwick , Joe Silk

Context. Galactic halos host faint substructures, such as stellar streams and shells, which provide insights into the hierarchical assembly history of galaxies. To date, such features have been identified in external galaxies by visual…

Although high-resolution N-body simulations make robust empirical predictions for the density distribution within cold dark matter halos, these studies have yielded little physical insight into the origins of the distribution. We…

Astrophysics · Physics 2008-11-26 Liliya L. R. Williams , Arif Babul , Julianne J. Dalcanton