Not so lumpy after all: modelling the depletion of dark matter subhaloes by Milky Way-like galaxies

By S. Garrison-Kimmel, Andrew Wetzel, James S. Bullock, P. Hopkins, M. Boylan-Kolchin, C. Faucher-Giguére, D. Keres̆, E. Quataert, R. Sanderson, A. Graus and 1 more. 2017

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Among the most important goals in cosmology is detecting and quantifying small (M_(halo)≃10^(6−9) M⊙) dark matter (DM) subhaloes. Current probes around the Milky Way (MW) are most sensitive to such substructure within ∼20 kpc of the halo centre, where the galaxy contributes significantly to the potential. We explore the effects of baryons on subhalo populations in ΛCDM using cosmological zoom-in baryonic simulations of MW-mass haloes from the Latte simulation suite, part of the Feedback In Realistic Environments (FIRE) project. Specifically, we compare simulations of the same two haloes run using (1) DM-only (DMO), (2) full baryonic physics and (3) DM with an embedded disc potential grown to match the FIRE simulation. Relative to baryonic simulations, DMO simulations contain ∼2 × as many subhaloes within 100 kpc of the halo centre; this excess is ≳5 × within 25 kpc. At z = 0, the baryonic simulations are completely devoid of subhaloes down to 3×10^6M⊙ within 15 kpc of the MW-mass galaxy, and fewer than 20 surviving subhaloes have orbital pericentres <20 kpc. Despite the complexities of baryonic physics, the simple addition of an embedded central disc potential to DMO simulations reproduces this subhalo depletion, including trends with radius, remarkably well. Thus, the additional tidal field from the central galaxy is the primary cause of subhalo depletion. Subhaloes on radial orbits that pass close to the central galaxy are preferentially destroyed, causing the surviving population to have tangentially biased orbits compared to DMO predictions. Our method of embedding a potential in DMO simulations provides a fast and accurate alternative to full baryonic simulations, thus enabling suites of cosmological simulations that can provide accurate and statistical predictions of substructure populations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/16ec33f3bef92c4cf63dd072c59b5361eef0961a

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Citations in the corpus

Milky Way Satellite Census. II. Galaxy–Halo Connection Constraints Including the Impact of the Large Magellanic Cloud (2019, methodology): “…our simulated subhalo populations, we apply a random forest algorithm trained on hydrodynamic simulations to predict the probability that each subhalo will be disrupted in a hydrodynamic re-simulation based on its orbital and internal properties (Garrison-Kimmel et al. 2017b; Nadler et al. 2018).”
Disruption of Dark Matter Substructure: Fact or Fiction? (2017, background): “…on how baryons may impact the abundance and demographics of dark matter substructure (e.g., Macciò et al. 2006; Weinberg et al. 2008; Dolag et al. 2009; Arraki et al. 2014; Brooks & Zolotov 2014; Despali & Vegetti 2016; Fiacconi et al. 2016; Wetzel et al. 2016; Garrison-Kimmel et al. 2017).”
The SAGA Survey. I. Satellite Galaxy Populations around Eight Milky Way Analogs (2017, background): “…mass function extracted from dark matter-only simulations may overpredict the actual subhalo abundance, as feedback within dwarf galaxies can change their properties and the neglected baryonic components, such as disks, can further disrupt subhalos (Wetzel et al. 2016; Garrison-Kimmel et al. 2017).”
The Local Group on FIRE: dwarf galaxy populations across a suite of hydrodynamic simulations (2018, background): “…2002), observational bias and incompleteness (e.g. Tollerud et al. 2008), and subhalo destruction due to the MW disc (D’Onghia et al. 2010; Garrison-Kimmel et al. 2017; Sawala et al. 2017), these solutions typically resolve the disparity by placing the known MW satellites in the largest…”
Milky Way Satellite Census. I. The Observational Selection Function for Milky Way Satellites in DES Y3 and Pan-STARRS DR1 (2019, methodology): “…suppress dwarf galaxy formation in low-mass halos (e.g., Bullock et al. 2000; Somerville 2002; Brown et al. 2014), and tidal interactions with the Galactic disk are expected to disrupt a significant number of systems (e.g., Garrison-Kimmel et al. 2017; Kelley et al. 2019; Nadler et al. 2018).”
The Spur and the Gap in GD-1: Dynamical Evidence for a Dark Substructure in the Milky Way Halo (2018, background): “Even after accounting for the destruction of subhalos due to the stellar disk (D’Onghia et al. 2010; Errani et al. 2017; Garrison-Kimmel et al. 2017), their density in the inner 20 kpc is high enough that a stream on a GD-1–like orbit is expected to have encountered at least one 106–107Me subhalo…”
Gravitational probes of dark matter physics (2017, background): “e small halos are more easily destroyed in hydrodynamic simulations as compared to their dark-matter-only analogues. This is largely 35 driven by the extra tidal eld of the central galaxy in the host [371, 358, 359], but also because the lower central density of subhalos in hydrodynamic simulations ”
Predicting the LISA white dwarf binary population in the Milky Way with cosmological simulations (2019, methodology): “We use a subset of MW-like galaxies from the Feedback in Realistic Environment (FIRE; Hopkins et al. 2014) project1, including m12i (a.k.a. the “Latte” simulation; Wetzel et al. 2016, m12m and m12f (Garrison-Kimmel et al. 2017) simulations.”
Dark Matter Substructure in Numerical Simulations: A Tale of Discreteness Noise, Runaway Instabilities, and Artificial Disruption (2018, background): “…on how baryons may impact the abundance and demographics of dark matter substructure(e.g., Macciò et al. 2006; Weinberg et al. 2008; Dolag et al. 2009; Arraki et al. 2014; Brooks & Zolotov 2014; Despali & Vegetti 2016; Fiacconi et al. 2016; Wetzel et al. 2016; Garrison-Kimmel et al. 2017).”
Mining for Dark Matter Substructure: Inferring Subhalo Population Properties from Strong Lenses with Machine Learning (2019, background): “…properties, theoretical uncertainties in the connection between stellar and halo properties (Nadler et al. 2019; Wechsler & Tinker 2018) and the eﬀect of baryons on the satellite galaxy population (Errani et al. 2017; Garrison-Kimmel et al. 2017; Brooks 2018; Fitts et al. 2018) pose a challenge.”
Small-Scale Challenges to the ΛCDM Paradigm (2017, background): “Figure 8 (modified from Garrison-Kimmel et al. 2017a) shows that the answer is likely “yes.””