The distribution and kinematics of early high-σ peaks in present-day haloes: implications for rare objects and old stellar populations

By J. Diemand, P. Madau, B. Moore, U. California, Santa Cruz, U. Zurich. 2005

153 citations recorded by the source corpus.

We show that the hierarchical assembly of cold dark matter haloes preserves the memory of the initial conditions. Using N-body cosmological simulations, we demonstrate that the present-day spatial distribution and kinematics of objects that formed within early (z? 10) protogalactic systems (old stars, satellite galaxies, globular clusters, massive black holes, etc.) depends mostly on the rarity of the peak of the primordial density field to which they originally belonged. Only for objects forming at lower redshifts does the exact formation site within the progenitor halo (e.g. whether near the centre or in an extended disc) become important. In present-day haloes, material from the rarer early peaks is more centrally concentrated and falls off more steeply with radius compared to the overall mass distribution, has a lower velocity dispersion, moves on more radial orbits, and has a more elongated shape. Population II stars that formed within protogalactic haloes collapsing from ≥2.5σ fluctuations would follow today an r -3.5 density profile with a half-light radius of 17 kpc and a velocity anisotropy that increases from isotropic in the inner regions to nearly radial at the halo edge. This agrees well with the radial velocity dispersion profile of Galaxy halo stars from the recent work of Battaglia et al. and with the anisotropic orbits of nearby halo stars.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/5086f0771456dad6293f09b89dd12d788a1b2523

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Citations in the corpus

WIDE-FIELD PRECISION KINEMATICS OF THE M87 GLOBULAR CLUSTER SYSTEM (2011, background): “…constraints, but they do illustrate conceptually the kind of inferences that one might make about the accretion history with more detailed models, e.g., based on the ellipticity, kinematics, and radial density profile of the GC system (Diemand et al. 2005; Moore et al. 2006; Griffen et al. 2010).”
A New View of the Dwarf Spheroidal Satellites of the Milky Way from VLT FLAMES: Where Are the Very Metal-poor Stars? (2006, background): “For example, if dSph were fossils of the pre-reionization era (Gnedin & Kravtsov 2006), the first stars in them could have been (partly) responsible for the reionization of the Universe and the metal-enrichment of the intergalactic medium (Bromm & Larson 2004).”
The Dark Matter Annihilation Signal from Galactic Substructure: Predictions for GLAST (2008, methodology): “Based on numerical convergence studies (Diemand et al. 2005a) we believe that we can trust the radial density profile of the VL-I host halo down to rconv = 3.4×10−3r200 = 1.3 kpc (Diemand et al. 2007a), corresponding to about 10◦ from the center.”
Dark matter cores all the way down (2015, background): “Indeed, it has already been noted that the spatial and orbit distribution of the surviving dwarfs is more consistent with these early biased peaks than that of the full subhalo distribution (Diemand et al. 2005; Moore et al. 2006; Lux et al. 2010).”
SIMULATIONS ON A MOVING MESH: THE CLUSTERED FORMATION OF POPULATION III PROTOSTARS (2011, background): “Specifically, such surveys should be focused on the Galactic bulge, where the Pop III survivors should preferentially reside due to the biasing of the minihalo formation sites (Diemand et al. 2005; Gao et al. 2010).”
Globular clusters, satellite galaxies and stellar haloes from early dark matter peaks (2005, background): “8 and table 4 in Diemand et al. (2005)].”
The stellar halo of the Galaxy (2008, methodology): “Diemand et al. (2005) provide an alternative view from dark matter only cosmological simulations.”
Numerical simulations of the dark universe: State of the art and the next decade (2012, background): “The latter effect is likely due to a combination of stronger tidal forces and the earlier collapse times of subhalos found close to the center [47].”
Cosmological simulations of the formation of the stellar haloes around disc galaxies (2011, methodology): “For example, Cooper et al. (2010) (see also Diemand et al. 2005), who applied a similar hybrid method to cosmological N-body simulations with ‘live’ galaxy potential wells, find a relatively steep distribution at small radii, with a logarithmic slope of ≈ −3.”
The Haunted Halos of Andromeda and Triangulum: A Panorama of Galaxy Formation in Action (2007, methodology): “Complementary studies using pure N-body simulations were undertaken by Diemand et al. (2005) and Gauthier, Dubinkski & Widrow (2006).”
The Luminosity Function of the Milky Way Satellites (2007, background): “For example, the satellites that are observed could be embedded only in the rarer, more massive dark sub-halos (Stoehr et al. 2002), or, the satellites may form only in the rare peaks of halos that were above a given mass at reionization (Diemand et al. 2005; Moore et al. 2006).”
WHY BARYONS MATTER: THE KINEMATICS OF DWARF SPHEROIDAL SATELLITES (2012, background): “…of galaxy formation in the CDM cosmological model, as galaxies that form at higher redshifts are more concentrated (Wechsler et al. 2002; Zhao et al. 2003), and early forming subhalos are found preferentially closer to the center of MW-mass galaxies (Diemand et al. 2005; Moore et al. 2006).”
Formation and Evolution of Galaxy Dark Matter Halos and Their Substructure (2007, background): “The run was completed in 320,000 CPU hours on NASA’s Project Columbia supercomputer, and follows the formation of a Milky Way-size halo with 234 million particles, an order of magnitude more than achieved previously.”