Dark Matter Subhalos and the Dwarf Satellites of the Milky Way

By P. Madau, J. Diemand, Michael Kuhlen. 2008

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The Via Lactea simulation of the cold dark matter halo of the Milky Way predicts the existence of many thousands of bound subhalos with masses above 106 M☉, distributed approximately with equal mass per decade of mass. Here we show that (1) a similar steeply rising subhalo mass function is also present at redshift z = 0.5 in an elliptical-sized halo simulated with comparable resolution in a different cosmology. Compared to Via Lactea, this run produces nearly a factor of 2 more subhalos with large circular velocities; (2) the fraction of Via Lactea mass brought in by subhalos that have a surviving bound remnant today reaches 45%. Most of the Via Lactea mass is acquired in resolved discrete clumps, with no evidence for a significant smooth infall; (3) because of tidal mass loss, the number of subhalos surviving today that reached a peak circular velocity of >10 km s−1 throughout their lifetime exceeds half a thousand, 5 times larger than their present-day abundance; (4) unless the circular velocity profiles of Galactic satellites peak at values significantly higher that expected from the stellar line-of-sight velocity dispersion, only about one in five subhalos with Vmax > 20 km s−1 today must be housing a luminous dwarf; (5) nearly 600 halos with masses greater than 107M☉ are found today in the ``field'' between r200 and 1.5r200, i.e. small dark matter clumps appear to be relatively inefficient at forming stars even well beyond the virial radius; 6) the observed Milky Way satellites appear to follow the overall dark matter distribution of Via Lactea, while the largest simulated subhalos today are found preferentially at larger radii; (7) subhalos have central densities that increase with Vmax and reach ρDM = 0.1–0.3 M☉ pc−3, comparable to the central densities inferred in dwarf spheroidals with core radii >250 pc.

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/7bf7ff33328812ba49fc62b042e6c5527be6a5d1

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Citations in the corpus

A BARYONIC SOLUTION TO THE MISSING SATELLITES PROBLEM (2012, background): “…IL, 60510; dhooper@fnal.gov Thoul & Weinberg 1996; Navarro & Steinmetz 1997; Klypin et al. 1999; Barkana & Loeb 1999; Gnedin 2000; Hoeft et al. 2006; Madau et al. 2008; Alvarez et al. 2009) or lower z due to blazars (Pfrommer et al. 2012), or due to cosmic ray heating (Wadepuhl & Springel 2011).”
Gravitational probes of dark matter physics (2017, background): “This can be more unambiguously measured and related in simulations and in observations than a relation between σLOS and vmax [318, 201, 319, 320, 249, 321].”
WHY BARYONS MATTER: THE KINEMATICS OF DWARF SPHEROIDAL SATELLITES (2012, background): “There are fewer small satellite galaxies orbiting our Milky Way (MW) galaxy than predicted by the favored Cold Dark Matter (CDM) cosmological model (Moore et al. 1999; Klypin et al. 1999; Madau et al. 2008; Wadepuhl & Springel 2011; Brooks et al. 2013).”
THE UNORTHODOX ORBITS OF SUBSTRUCTURE HALOS (2008, background): “Furthermore, the number density profile of the subhalo population also differs markedly from that of galaxies in clusters, and possibly from the radial distribution of luminous satellites around the Milky Way (Kravstov et al 2004; Willman et al 2004; Madau et al 2008).”
The flattening of the concentration–mass relation towards low halo masses and its implications for the annihilation signal boost (2013, background): “Values of α ranging between α = 1.9 and 2 are possible (Diemand et al. 2007; Madau et al. 2008; Springel et al. 2008).”
SEARCH FOR DARK MATTER SATELLITES USING FERMI-LAT (2012, unknown): “These low-mass satellites were distributed within this 50 kpc radius in accordance to the radial distribution described in Madau et al. (2008).”
BARYONS MATTER: WHY LUMINOUS SATELLITE GALAXIES HAVE REDUCED CENTRAL MASSES (2012, background): “…vc, at infall < 30 km/s (Quinn et al. 1996; Thoul & Weinberg 1996; Navarro & Steinmetz 1997; Gnedin 2000; Hoeft et al. 2006; Okamoto et al. 2008; Madau et al. 2008), and supernova feedback further suppressing star formation at the more massive subhalo end (Dekel & Silk 1986; Benson et al. 2002;…”
The Dark Matter Annihilation Signal from Galactic Substructure: Predictions for GLAST (2008, background): “(A4) Note that this anti-biased spatial distribution is motivated by numerical simulations (Kuhlen et al. 2007; Madau et al. 2008) and differs from the distribution chosen by Pieri et al. (2008), who employed an unbiased distribution of the form dnsub dM (M,R) = AM−2 H(R − rmin(M)) (R/rMWs )(1 +R/r…”
THE LEAST-LUMINOUS GALAXY: SPECTROSCOPY OF THE MILKY WAY SATELLITE SEGUE 1 (2008, background): “These objects provide important clues to galaxy formation on the smallest scales (Madau et al. 2008; Ricotti et al. 2008) and substantially alleviate the discrepancy between the observed mass function of Milky Way satellites and that predicted by standard Lambda Cold Dark Matter models (Tollerud et…”
PRE-REIONIZATION FOSSILS, ULTRA-FAINT DWARFS, AND THE MISSING GALACTIC SATELLITE PROBLEM (2008, background): “N-body simulations show that the number N (M) of Milky Way dark matter satellites as a function of their mass is not overly sensitive to the cosmology, although there are some differences on the number of the most massive satellites (Madau et al. 2008).”
The Aquarius Project: the subhaloes of galactic haloes (2008, result): “We note that our results disagree with those of the re- cent Via Lactea I and II simulations (Diemand et al., 2007a; Madau et al., 2008; Diemand et al., 2008; Kuhlen et al., 2008) on several important points.”
EVOLUTION OF THE GALAXY–DARK MATTER CONNECTION AND THE ASSEMBLY OF GALAXIES IN DARK MATTER HALOS (2011, background): “…a large scatter may be exactly what is needed to reconcile the observed satellite population of the MW with predictions from ΛCDM cosmologies (e.g,., Madau et al. 2008), and may already have observational support from the fact that the ultrafaint dwarfs appear to reside in halos of similar mass as…”
Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function (2008, methodology): “Note that while the mass of Via Lactea is quite close to that obtained from CDM-based mass models of the Milky Way (e.g., Klypin et al. 2002; Madau et al. 2008), the mass of the Milky Way halo is constrained by observations only at the factor of 2 level.”
Mining for Dark Matter Substructure: Inferring Subhalo Population Properties from Strong Lenses with Machine Learning (2019, methodology): “9 (Madau et al. 2008; Springel et al. 2008), resulting in a nearly scale-invariant spectrum of subhalos, which we assume in our ﬁducial setup.”
The Milky Way’s bright satellites as an apparent failure of ΛCDM (2011, methodology): “Strigari et al. (2007b), Madau et al. (2008a), and Kuhlen (2010) have previously used the Via Lactea simulations to derive constraints on Vmax (and, in the case of Kuhlen 2010, Vinfall) values.”
The haloes of bright satellite galaxies in a warm dark matter universe (2011, methodology): “Using also the Aquarius haloes, as well as the Via Lactea simulations (Madau et al. 2008), they show explicitly that the simulated haloes typically contain a few subhaloes which are too massive and too dense (as indicated by their value of Vmax/rmax) to host any of the observed satellites.”