Bibcode
McCarthy, I. G.; Schaye, J.; Dalla Vecchia, C.; Furlong, M.; Crain, R. A.; Theuns, T.; Trayford, J.; Frenk, C. S.; Bower, R. G.; Schaller, M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 452, Issue 1, p.343-355
Advertised on:
9
2015
Citations
92
Refereed citations
87
Description
We use the `Evolution and assembly of galaxies and their environments'
(EAGLE) cosmological simulation to investigate the effect of baryons on
the density profiles of rich galaxy clusters. We focus on EAGLE clusters
with M200 > 1014 M⊙ of which we
have six examples. The central brightest cluster galaxies (BCGs) in the
simulation have steep stellar density profiles, ρ*(r)
∝ r-3. Stars dominate the mass density for r < 10
kpc, and, as a result, the total mass density profiles are steeper than
the Navarro-Frenk-White (NFW) profile, in remarkable agreement with
observations. The dark matter halo itself closely follows the NFW form
at all resolved radii (r ≳ 3.0 kpc). The EAGLE BCGs have similar
surface brightness and line-of-sight velocity dispersion profiles as the
BCGs in the sample of Newman et al., which have the most detailed
measurements currently available. After subtracting the contribution of
the stars to the central density, Newman et al. infer significantly
shallower slopes than the NFW value, in contradiction with the EAGLE
results. We discuss possible reasons for this discrepancy, and conclude
that an inconsistency between the kinematical model adopted by Newman et
al. for their BCGs, which assumes isotropic stellar orbits, and the
kinematical structure of the EAGLE BCGs, in which the orbital stellar
anisotropy varies with radius and tends to be radially biased, could
explain at least part of the discrepancy.
Related projects
Numerical Astrophysics: Galaxy Formation and Evolution
How galaxies formed and evolved through cosmic time is one of the key questions of modern astronomy and astrophysics. Cosmological time- and length-scales are so large that the evolution of individual galaxies cannot be directly observed. Only through numerical simulations can one follow the emergence of cosmic structures within the current
Claudio
Dalla Vecchia