Related papers: Star Stream Folding by Dark Galactic Sub-Halos
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…
The dark matter subhalos orbiting in a galactic halo perturb the orbits of stars in thin stellar streams. Over time the random velocities in the streams develop non-Gaussian wings. The rate of velocity increase is approximately a random…
Thin halo star streams originate from the evaporation of globular clusters and therefore provide information about the early epoch globular cluster population. The observed tidal tails from halo globular clusters in the Milky Way are much…
The velocity, position, and action variable evolution of a tidal stream drawn out of a star cluster in a triaxial isochrone potential containing a sub-halo population reproduces many of the orbital effects of more general cosmological halos…
Simulations are run with and without a normal cold dark matter sub-halo population below 4x10^8 M_sun to examine the role of the lower mass sub-halos in the creation of density variations, "gaps", within thin tidal star streams. Dense star…
We explore the phase-space structure of nearby halo stars identified kinematically from Gaia DR2 data. We focus on their distribution in velocity and in "integrals of motion" space as well as on their photometric properties. Our sample of…
Measurements of velocity and density perturbations along stellar streams in the Milky Way provide a time integrated measure of dark matter substructure at larger galactic radius than the complementary instantaneous inner halo strong lensing…
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.…
Recent years have seen the discovery of an ever growing number of stellar debris streams and clouds. These structures are typically detected as extended and often curvilinear overdensities of metal-poor stars that stand out from the…
We have detected stellar halo streams in the solar neighborhood using data from the 7th public data release of the Sloan Digital Sky Survey (SDSS), which includes the directed stellar program SEGUE: Sloan Extension For Galactic…
Measurements of the GD-1 star stream velocity distribution within $\pm$3 degrees of the centerline find a total line of sight velocity spread of 5-6 km/s in the well measured $\phi_1=$ [-30, 0] region (Valluri25). The velocity spread is far…
When a massive object crosses a star stream velocity changes are induced both along and transverse to the stream which can lead to the development of a visible gap. For a stream narrow relative to its orbital radius the time of stream…
The Cold Dark Matter paradigm predicts vast numbers of dark matter sub-halos to be orbiting in galactic halos. The sub-halos are detectable through the gaps they create gaps in stellar streams. The gap-rate is an integral over the density…
We study numerical simulations of satellite galaxy disruption in a potential resembling that of the Milky Way. Our goal is to assess whether a merger origin for the stellar halo would leave observable fossil structure in the phase-space…
We use 666 blue horizontal branch (BHB) stars from the 2Qz redshift survey to map the Galactic halo in four dimensions (position, distance and velocity). We find that the halo extends to at least 100 kpc in Galactocentric distance, and…
In the prevailing model of galaxy formation and evolution, the process of gas accretion onto central galaxies undergoes a transition from cold-dominated to hot-dominated modes. This shift occurs when the mass of the parent dark matter halos…
In this contribution we discuss the expected properties of our halo if our Galaxy had been built from mergers of smaller systems. Using both analytic arguments and high-resolution simulations, we find that the Galactic halo in the Solar…
We use the very high resolution, fully cosmological simulations from the Aquarius project, coupled to a semi-analytical model of galaxy formation, to study the phase-space distribution of halo stars in "solar neighbourhood"-like volumes. We…
Stellar streams, long, thin streams of stars, have been used as sensitive probes of dark matter substructure for over two decades. Gravitational interactions between dark matter substructures and streams lead to the formation of low-density…
The C-19 star stream has the abundance characteristics of an unusually metal poor globular cluster but kinematically is uncharacteristically hot and wide for a cluster stream, having a line of sight velocity dispersion of 7 +/- 2 km/s and a…