CLUMPY STREAMS FROM CLUMPY HALOS: DETECTING MISSING SATELLITES WITH COLD STELLAR STRUCTURES

By J. Yoon, K. Johnston, David W. Hogg. 2010

138 citations recorded by the source corpus.

Dynamically cold stellar streams are ideal probes of the gravitational field of the Milky Way. This paper re-examines the question of how such streams might be used to test for the presence of “missing satellites”—the many thousands of dark-matter subhalos with masses 105–107 M☉ which are seen to orbit within Galactic-scale dark-matter halos in simulations of structure formation in ΛCDM cosmologies. Analytical estimates of the frequency and energy scales of stream encounters indicate that these missing satellites should have a negligible effect on hot debris structures, such as the tails from the Sagittarius dwarf galaxy. However, long cold streams, such as the structure known as GD1 or those from the globular cluster Palomar 5 (Pal 5), are expected to suffer many tens of direct impacts from missing satellites during their lifetimes. Numerical experiments confirm that these impacts create gaps in the debris’ orbital energy distribution, which will evolve into degree- and sub-degree-scale fluctuations in surface density over the age of the debris. Maps of Pal 5's own stream contain surface density fluctuations on these scales. The presence and frequency of these inhomogeneities suggests the existence of a population of missing satellites in numbers predicted in the standard ΛCDM cosmologies.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/7df9d4fb3033490a97fe472f1023b133b2ade6ca

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Citations in the corpus

`Skinny Milky Way please', says Sagittarius (2014, methodology): “The inclination of the ellipse can be approximated using the expressions for particle excursions in (E, L) space presented in Equation 10 of Yoon et al. (2011).”
Numerical simulations of the dark universe: State of the art and the next decade (2012, background): “Additionally, cold stellar streams associated with the disruption of globular clusters [71] are promising probes of the clumpiness of the Milky Way’s DM halo, since interactions with passing subhalos should produce kinks and gaps the stream [72, 73].”
Not so lumpy after all: modelling the depletion of dark matter subhaloes by Milky Way-like galaxies (2017, background): “While Vmax can be measured robustly in simulations, the degree to which a subhalo disrupts a stellar stream is more closely related to its bound mass (along with the interaction distance and velocity; e.g. Yoon et al. 2011; Carlberg 2013; Sanders et al. 2016; Sanderson et al. 2016).”
Project Overview of the Beijing–Arizona Sky Survey (2017, background): “Our deep imaging data will not only test this prediction, but also test the presence of additional satellite galaxies through their impact on the well known stream structures (Yoon et al. 2011).”
The current status of galaxy formation (2012, background): “Numerical simulations (Yoon et al., 2011) find that high M/L satellites of mass ∼ 107 M are required, again a prediction of the CDM model.”