The apostle project: Local Group kinematic mass constraints and simulation candidate selection
Year: 2016
Type: article
Abstract: 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 × 1012 M⊙. 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 × 1012 M⊙ for the apostle project (A Project Of Simulating The Local Environment), a suite of hydrodynamical resimulations at various numerical resolution levels (reaching up to ∼104 M⊙ 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 Λ cold dark matter cosmology with observations of our local Universe.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, Aspen Center for Physics, Compute Canada, Western Canada Research Grid, Leverhulme Trust, European Commission, Durham University, Belgian Federal Science Policy Office, University of California, Santa Barbara, Science and Technology Facilities Council, Kavli Institute for Theoretical Physics, University of California, Santa Barbara, FP7 Ideas: European Research Council
Awards: G1381339075, Durham DiRAC-2 petascale facility, G2038892709, G2288345500, From the Milky Way to the cosmic large-scale structure, G2639239629, G2918681272, G3090041109, G3207356259, G3467815775, G3478530172, G3531124447, G393177772, G4104599821, G432354605, G4357913612, G4433229824, G4773563968, G4831232377, Programs on Critical Problems in Physics, Astrophysics and Biophysics at the Aspen Center for Physics, G5702163051, G6583118092, G7165083805, G764792286, G8092745986, The Virgo consortium for cosmological supercomputer simulations, Durham DiRAC-2 petascale facility support, G8896167186, G8986044568
OpenAlex ID: W1505073781