The APOSTLE project: Local Group kinematic mass constraints and simulation candidate selection

By Azadeh Fattahi, J. Navarro, T. Sawala, Carlos S. Frenk, K. Oman, Robert A. Crain, Michelle Furlong, Matthieu Schaller, Joop Schaye, Tom Theuns and 1 more. 2015

153 citations recorded by the source corpus.

We use a large sample of isolated dark matter halo pairs drawn from cosmological N-body simulations to identify candidate systems whose kinematics match that of the Local Group (LG) of galaxies. We find, in agreement with the ‘timing argument’ and earlier work, that the separation and approach velocity of the Milky Way (MW) and Andromeda (M31) galaxies favour a total mass for the pair of ∼5 × 1012M . A mass this large, however, is difficult to reconcile with the small relative tangential velocity of the pair, as well as with the small deceleration from the Hubble flow observed for the most distant LG members. Halo pairs that match these three criteria have average masses a factor of ∼2 times smaller than suggested by the timing argument, but with large dispersion. Guided by these results, we have selected 12 halo pairs with total mass in the range 1.6–3.6 × 1012M for the APOSTLE project (A Project Of Simulating The Local Environment), a suite of hydrodynamical resimulations at various numerical resolution levels (reaching up to ∼104M per gas particle) that use the subgrid physics developed for the EAGLE project. These simulations reproduce, by construction, the main kinematics of the MW–M31 pair, and produce satellite populations whose overall number, luminosities, and kinematics are in good agreement with observations of the MW and M31 companions. The APOSTLE candidate systems thus provide an excellent testbed to confront directly many of the predictions of the cold dark matter cosmology with observations of our local Universe.

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

View Paper: https://www.semanticscholar.org/paper/3341cac7c85c35040c04bb19e4331648cce59047

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Citations in the corpus

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.”
The Local Group on FIRE: dwarf galaxy populations across a suite of hydrodynamic simulations (2018, methodology): “The APOSTLE simulations (Fattahi et al. 2016b; Sawala et al. 2016b), for example, apply the EAGLE models for galaxy formation, which are tuned to reproduce the stellar mass function (SMF) and sizes of galaxies at z = 0.1 (Crain et al. 2015; Schaye et al. 2015), to 12 LG-like volumes,2 1The Auriga…”
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].”
The milky way total mass profile as inferred from Gaia DR2 (2019, methodology): “Our final sample consist of 33 medium-resolution and 5 high-resolution Auriga haloes, 16 medium-resolution and 6 high-resolution APOSTLE haloes, and 27 EAGLE_recal haloes.”
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).”