The Tumultuous Lives of Galactic Dwarfs and the Missing Satellites Problem

By Andrey V. Kravtsov, O. Gnedin, Anatoly Klypin. 2004

501 citations recorded by the source corpus.

Hierarchical cold dark matter (CDM) models predict that Milky Way-sized halos contain several hundred dense low-mass dark matter satellites (the substructure), an order of magnitude more than the number of observed satellites in the Local Group. If the CDM paradigm is correct, this prediction implies that the Milky Way and Andromeda are filled with numerous dark halos. To understand why these halos failed to form stars and become galaxies, we need to understand their history. We analyze the dynamical evolution of the substructure halos in a high-resolution cosmological simulation of Milky Way-sized halos in the ΛCDM cosmology. We find that about 10% of the substructure halos with the present masses ≲108-109 M☉ (circular velocities Vm ≲ 30 km s-1) had considerably larger masses and circular velocities when they formed at redshifts z ≳ 2. After the initial period of mass accretion in isolation, these objects experience dramatic mass loss because of tidal stripping. Our analysis shows that strong tidal interaction is often caused by actively merging massive neighboring halos, even before the satellites are accreted by their host halo. These results can explain how the smallest dwarf spheroidal galaxies of the Local Group were able to build up a sizable stellar mass in their seemingly shallow potential wells. We propose a new model in which all the luminous dwarf spheroidals in the Local Group are descendants of the relatively massive (≳109 M☉) high-redshift systems, in which the gas could cool efficiently by atomic line emission, and which were not significantly affected by the extragalactic ultraviolet radiation. We present a simple galaxy formation model based on the trajectories extracted from the simulation, which accounts for the bursts of star formation after strong tidal shocks and the inefficiency of gas cooling in halos with virial temperatures Tvir ≲ 104 K. Our model reproduces the abundance, spatial distribution, and morphological segregation of the observed Galactic satellites. The results are insensitive to the redshift of reionization.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/6149aa81e30a8f3583ade0ecdc77f10ace1da2f8

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Citations in the corpus

ENVIRONMENTAL DEPENDENCE OF THE KENNICUTT–SCHMIDT RELATION IN GALAXIES (2010, methodology): “Such a recipe can be used in semi-analytic models, in which radial dependence of gas surface density, star formation, and chemical enrichment are modeled explicitly (e.g., Firmani & Avila-Reese 2000; Kravtsov et al. 2004; Dutton et al. 2007).”
The Great disk of Milky Way satellites and cosmological sub-structures (2004, background): “The theoretical sub-structure distribution of MW-type hosts must therefore be essentially isotropic (Ghigna et al. 1998; Zentner & Bullock 2003; Diemand et al. 2004; Kravtsov et al. 2004; Aubert et al. 2004).”
THE SPACE MOTION OF LEO I: THE MASS OF THE MILKY WAY'S DARK MATTER HALO (2012, background): “…and the most massive subhalos for some suitable definition of mass, most often the maximum mass or circular velocity that the subhalo has ever had (e.g., Kravtsov et al. 2004; Conroy et al. 2006; Guo et al. 2010; Yang et al. 2012; Reddick et al. 2012; Behroozi et al. 2012; Moster et al. 2013).”
Halo Assembly Bias in Hierarchical Structure Formation (2008, methodology): “A similar method for subhalo tracking has been employed by Springel et al. (2005), Faltenbacher et al. (2005), Kravtsov et al. (2004), Allgood et al. (2006), and Harker et al. (2006).”
The stellar halo of the Galaxy (2008, background): “…and this is where environmental effects and processes such as reionization, feedback from massive stars, etc. are likely to have a significant impact on the probability of a substructure to hold onto its gas and form stars (e.g. Mac Low & Ferrara 1999; Bullock et al. 2000; Kravtsov et al. 2004).”
Small scale problems of the $\Lambda$CDM model: a short review (2016, background): “tible to tidal stripping and even to tidal destruction [77,374]. This picture would see the present-day dwarf galaxies, more massive in the past, transformed and reduced strong tidal stripping (e.g., [392]); b.The suppression of star formation from (a)Supernova feedback (SF) (b)Photo-ionisation [74,”
A New Milky Way Companion: Unusual Globular Cluster or Extreme Dwarf Satellite? (2004, background): “The relationship between GCs and dSphs is particularly interesting in light of recent predictions for low-mass substructure around the Milky Way (Klypin et al. 1999; Moore et al. 1999; Bullock et al. 2000; Benson et al. 2002; Susa &Umemura 2004; Kravtsov et al. 2004, among others).”
There's no place like home? Statistics of Milky Way-mass dark matter haloes (2009, background): “All studies have found that α2 ≈ 1 over a wide range in mass and have concluded that the scatter is indeed Poissonian (e.g., Kravtsov et al. 2004a; Zheng et al. 2005).”
Characterization of subhalo structural properties and implications for dark matter annihilation signals (2016, background): “Tidal stripping removes mass from the outer parts of subhalos and, as a result, subhalos are truncated at smaller radii compared to field halos of the same mass (Ghigna et al. 1998; Taylor & Babul 2001; Kravtsov et al. 2004; Diemand et al. 2007a,b).”
Dark Matter Subhalos and the Dwarf Satellites of the Milky Way (2008, background): “…general model has been investigated by a number of authors in the recent literature (e.g. Bullock et al. 2000; Benson et al. 2002; Somerville 2002; Kravtsov et al. 2004; Ricotti & Gnedin 2005; Moore et al. 2006; Diemand et al. 2007a; Strigari et al. 2007a; Simon & Geha 2007), there are…”
The population of dark matter subhaloes: mass functions and average mass-loss rates (2007, background): “Journal compilation C© 2008 RAS nloaded from https://academ ic.oup.com /m nras/article-abstract/386/4/2135/1463407 by guest on 13 D ecem ber 2018 Somerville 2002; Kravtsov et al. 2004b; Vale & Ostriker 2006).”
The Baryon Content of Extremely Low Mass Dwarf Galaxies (2006, background): “Some of these processes only occur for dwarf galaxies near a luminous galaxy and not for isolated – 3 – ones (Kravtsov et al. 2004).”
A QUANTITATIVE EXPLANATION OF THE OBSERVED POPULATION OF MILKY WAY SATELLITE GALAXIES (2009, methodology): “Kravtsov et al. (2004) used N-body simulations to show that roughly 10% of sub-halos lose a large fraction (∼ 90”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “A combination of supernovae feedback, reionization and ram-pressure stripping is sufficient to fully explain the observed distribution assuming pure CDM [529, 756, 603].”
Luminosity function and radial distribution of Milky Way satellites in a ΛCDM Universe (2009, methodology): “Thus, unlike previous studies (e.g. Benson et al. 2002; Somerville 2002; Kravtsov et al. 2004) which compared only with the “classical” satellite population MV = −9, we can resolve the very small subhaloes that may host the newly detected population of ultra-faint satellites.”