Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2010-02-17
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
17 pages, 14 figures, MNRAS accepted after minor revision
Scientific paper
(Abridged) We use N-body simulations to study the effects that a divergent (i.e. "cuspy") dark matter (DM) profile introduces on the tidal evolution of dwarf spheroidal galaxies (dSphs). Our models assume cosmologically-motivated initial conditions where dSphs are DM-dominated systems on eccentric orbits about a host galaxy composed of a dark halo and a baryonic disc. We find that the resilience of dSphs to tidal stripping is extremely sensitive to the halo cuspiness; whereas dwarfs with a cored profile can be easily destroyed by the host disc, those with cusps always retain a bound remnant. For a given halo profile the evolution of the structural parameters as driven by tides is controlled solely by the total amount of mass lost. This information is used to construct a semi-analytic code that simulates the hierarchical build-up of spiral galaxies assuming different halo profiles and disc masses. We find that tidal encounters with discs tend to decrease the average mass of satellites at all galactocentric radii. Interestingly, satellites accreted before re-ionization (z>6), which may be singled out by anomalous metallicity patterns, survive only if haloes are cuspy. We show that the size-mass relation established from Milky Way (MW) dwarfs strongly supports the presence of cusps in the majority of these systems, as cored models systematically underestimate the masses of the known Ultra-Faint dSphs. Our models also indicate that a massive M31 disc may explain why many of its dSphs fall below the size-mass relationship derived from MW dSphs. We use our models to constrain the mass threshold below which star formation is suppressed in DM haloes, finding that luminous satellites must be accreted with masses above 10^8--10^9 M_sol in order to explain the size-mass relation observed in MW dwarfs.
Benson Andrew J.
Gilmore Gerard
Mayer Lucio
McConnachie Alan
Penarrubia Jorge
No associations
LandOfFree
The impact of dark matter cusps and cores on the satellite galaxy population around spiral galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The impact of dark matter cusps and cores on the satellite galaxy population around spiral galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The impact of dark matter cusps and cores on the satellite galaxy population around spiral galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-404373