The APOSTLE simulations: solutions to the Local Group's cosmic puzzles

By T. Sawala, Carlos S. Frenk, Azadeh Fattahi, J. Navarro, Richard G. Bower, Robert A. Crain, Claudio Dalla Vecchia, Michelle Furlong, John C. Helly, Adrian Jenkins and 18 more. 2015

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The Local Group of galaxies offer some of the most discriminating tests of models of cosmic structure formation. For example, observations of the Milky Way (MW) and Andromeda satellite populations appear to be in disagreement with N-body simulations of the "Lambda Cold Dark Matter" ({\Lambda}CDM) model: there are far fewer satellite galaxies than substructures in cold dark matter halos (the "missing satellites" problem); dwarf galaxies seem to avoid the most massive substructures (the "too-big-to-fail" problem); and the brightest satellites appear to orbit their host galaxies on a thin plane (the "planes of satellites" problem). Here we present results from APOSTLE (A Project Of Simulating The Local Environment), a suite of cosmological hydrodynamic simulations of twelve volumes selected to match the kinematics of the Local Group (LG) members. Applying the Eagle code to the LG environment, we find that our simulations match the observed abundance of LG galaxies, including the satellite galaxies of the MW and Andromeda. Due to changes to the structure of halos and the evolution in the LG environment, the simulations reproduce the observed relation between stellar mass and velocity dispersion of individual dwarf spheroidal galaxies without necessitating the formation of cores in their dark matter profiles. Satellite systems form with a range of spatial anisotropies, including one similar to that of the MW, confirming that such a configuration is not unexpected in {\Lambda}CDM. Finally, based on the observed velocity dispersion, size, and stellar mass, we provide new estimates of the maximum circular velocity for the halos of nine MW dwarf spheroidals.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a868a76940557c938dbd55066ed959ce02e3a55c

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Citations in the corpus

Probing Galactic Halos with Fast Radio Bursts (2019, background): “Sawala et al. (2016) have generated a series of hydrodynamical simulations (named APOSTLE) designed to mimic our Local Group with scientific focus on its satellite systems.”
Rapid Reionization by the Oligarchs: The Case for Massive, UV-bright, Star-forming Galaxies with High Escape Fractions (2019, methodology): “The Tacchella et al. (2018) model is built on top of a 10 Mpc6 3, high-resolution, N-body, dark-matter simulation, COLOR (Hellwing et al. 2016; Sawala et al. 2016).”
Not so lumpy after all: modelling the depletion of dark matter subhaloes by Milky Way-like galaxies (2017, methodology): “…to DMO simu- MNRAS 000, 1–19 (2017) lations could capture the key baryonic effects on dark subhalos (e.g. D’Onghia et al. 2010; Zhu et al. 2016; Sawala et al. 2016a; Errani et al. 2017; Jethwa et al. 2016), we apply a method for inserting an approximate analytic description of the…”
Quenching and ram pressure stripping of simulated Milky Way satellite galaxies (2017, methodology): “An exception is the APOSTLE simulations, a set of 12 cosmological zoom simulations of Local Group-like volumes (Fattahi et al. 2016; Sawala et al. 2016a,b).”
FIRE in the field: Simulating the threshold of galaxy formation (2016, methodology): “Most modern high-resolution simulation suites are designed to cover a wide range of halo masses (Munshi et al. 2013; Chan et al. 2015; Wang et al. 2015; Sawala et al. 2016).”
RECONCILING DWARF GALAXIES WITH ΛCDM COSMOLOGY: SIMULATING A REALISTIC POPULATION OF SATELLITES AROUND A MILKY WAY–MASS GALAXY (2016, background): “…and with more realistic stellar physics (e.g., Hopkins et al. 2014; Agertz & Kravtsov 2015; Mollitor et al. 2015), and some simulations have started to resolve the more massive satellite galaxies within MW-mass halos, with promising results (e.g., Brooks & Zolotov 2014; Sawala et al. 2016).”
The milky way total mass profile as inferred from Gaia DR2 (2019, methodology): “APOSTLE is a suite of 12 pairs of MW-mass haloes selected to resemble the Local Group in terms of mass, separation, relative velocity and local environment (Fattahi et al. 2016; Sawala et al. 2016a).”
Small scale problems of the $\Lambda$CDM model: a short review (2016, background): “the APOSTLE project [119,142] — claimed to have successfully reproduced the BTFR over four decades [143], even reproducing its break-down at the faint end, as was indeed observed [68,144].”
On the estimation of the local dark matter density using the rotation curve of the Milky Way (2019, unknown): “[49, 50]).”
Gravitational probes of dark matter physics (2017, background): “If the missing satellites problem is cast in terms of a luminosity or stellar mass function, there is a similar level of agreement on classical dwarf scales [373, 387].”
Milky Way Satellite Census. II. Galaxy–Halo Connection Constraints Including the Impact of the Large Magellanic Cloud (2019, methodology): “A wide range of galaxy occupation fractions have been reported in hydrodynamic simulations, with some placingM50 as high as ∼ 109 M (Sawala et al. 2016b; Fitts et al. 2018).”
The stellar mass-halo mass relation of isolated field dwarfs : a critical test of ΛCDM at the edge of galaxy formation (2016, background): “In Read et al. 1 Two recent studies have claimed that dark matter cores do not form at any mass scale (Sawala et al. 2016b; Zhu et al. 2016).”
A Redshift-independent Efficiency Model: Star Formation and Stellar Masses in Dark Matter Halos at z ≳ 4 (2018, methodology): “Zoom-in simulations based on color have appeared as part of the coco (Hellwing et al. 2016; Bose et al. 2016) and apostle (Fattahi et al. 2016; Sawala et al. 2016) suite of simulations.”
First results from the TNG50 simulation: galactic outflows driven by supernovae and black hole feedback (2019, background): “…of order 10 to 100 galaxies in total (Wang et al. 2015), often oriented around a focus such as Milky Way mass halos (Grand et al. 2017), Local Group analogs (Sawala et al. 2016) or the challenging regime of galaxies in high-density cluster environments (Bahé et al. 2017; Tremmel et al. 2018).”
The Local Group on FIRE: dwarf galaxy populations across a suite of hydrodynamic simulations (2018, methodology): “6 of Sawala et al. (2016b) and fig.”
ETHOS - an effective theory of structure formation: dark matter physics as a possible explanation of the small-scale CDM problems (2015, background): “4 of Sawala et al. 2016) Finally, we show the (radially averaged) internal structure of subhaloes in Fig.”