We present initial results from the "Ponos" zoom-in numerical simulations of dark matter substructures in massive ellipticals. Two very highly resolved dark matter halos with M vir = 1.2 × 1013 and M vir = 6.5 1012 and different (violent versus quiescent) assembly histories have been simulated down to z = 0 in a ΛCDM cosmology with a total of 921,651,914 and 408,377,544 particles, respectively. Within the virial radius, the total mass fraction in self-bound M sub > 106 subhalos at the present epoch is 15% for the violent host and 16.5% for the quiescent one. At z = 0.7, these fractions increase to 19% and 33%, respectively, as more recently accreted satellites are less prone to tidal destruction. In projection, the average fraction of surface mass density in substructure at a distance of R/R vir = 0.02 (∼5-10 kpc) from the two halo centers ranges from 0.6% to 2%, significantly higher than that measured in simulations of Milky Way-sized halos. The contribution of subhalos with M sub < 109 to the projected mass fraction is between one-fifth and one-third of the total, with the smallest share found in the quiescent host. We assess the impact of baryonic effects via twin, lower-resolution hydrodynamical simulations that include metallicity-dependent gas cooling, star formation, and a delayed-radiative-cooling scheme for supernova feedback. Baryonic contraction produces a super-isothermal total density profile and increases the number of massive subhalos in the inner regions of the main host. The host density profiles and projected subhalo mass fractions appear to be broadly consistent with observations of gravitational lenses.

Fiacconi, D., Madau, P., Potter, D., Stadel, J. (2016). COLD DARK MATTER SUBSTRUCTURES in EARLY-TYPE GALAXY HALOS. THE ASTROPHYSICAL JOURNAL, 824(2) [10.3847/0004-637X/824/2/144].

COLD DARK MATTER SUBSTRUCTURES in EARLY-TYPE GALAXY HALOS

Madau P.;
2016

Abstract

We present initial results from the "Ponos" zoom-in numerical simulations of dark matter substructures in massive ellipticals. Two very highly resolved dark matter halos with M vir = 1.2 × 1013 and M vir = 6.5 1012 and different (violent versus quiescent) assembly histories have been simulated down to z = 0 in a ΛCDM cosmology with a total of 921,651,914 and 408,377,544 particles, respectively. Within the virial radius, the total mass fraction in self-bound M sub > 106 subhalos at the present epoch is 15% for the violent host and 16.5% for the quiescent one. At z = 0.7, these fractions increase to 19% and 33%, respectively, as more recently accreted satellites are less prone to tidal destruction. In projection, the average fraction of surface mass density in substructure at a distance of R/R vir = 0.02 (∼5-10 kpc) from the two halo centers ranges from 0.6% to 2%, significantly higher than that measured in simulations of Milky Way-sized halos. The contribution of subhalos with M sub < 109 to the projected mass fraction is between one-fifth and one-third of the total, with the smallest share found in the quiescent host. We assess the impact of baryonic effects via twin, lower-resolution hydrodynamical simulations that include metallicity-dependent gas cooling, star formation, and a delayed-radiative-cooling scheme for supernova feedback. Baryonic contraction produces a super-isothermal total density profile and increases the number of massive subhalos in the inner regions of the main host. The host density profiles and projected subhalo mass fractions appear to be broadly consistent with observations of gravitational lenses.
Articolo in rivista - Articolo scientifico
Cosmology: theory; dark matter; galaxies: halos; gravitational lensing: strong; methods: numerical;
English
2016
824
2
144
none
Fiacconi, D., Madau, P., Potter, D., Stadel, J. (2016). COLD DARK MATTER SUBSTRUCTURES in EARLY-TYPE GALAXY HALOS. THE ASTROPHYSICAL JOURNAL, 824(2) [10.3847/0004-637X/824/2/144].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/452319
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