Bibcode
Velliscig, M.; van Daalen, Marcel P.; Schaye, Joop; McCarthy, Ian G.; Cacciato, Marcello; Le Brun, Amandine M. C.; Dalla Vecchia, C.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 442, Issue 3, p.2641-2658
Fecha de publicación:
8
2014
Número de citas
159
Número de citas referidas
148
Descripción
We use cosmological hydrodynamical simulations to investigate how the
inclusion of physical processes relevant to galaxy formation (star
formation, metal-line cooling, stellar winds, supernovae and feedback
from active galactic nuclei, AGN) change the properties of haloes, over
four orders of magnitude in mass. We find that gas expulsion and the
associated dark matter (DM) expansion induced by supernova-driven winds
are important for haloes with masses M200 ≲
1013 M⊙, lowering their masses by up to 20 per
cent relative to a DM-only model. AGN feedback, which is required to
prevent overcooling, has a significant impact on halo masses all the way
up to cluster scales (M200 ˜ 1015
M⊙). Baryon physics changes the total mass profiles of
haloes out to several times the virial radius, a modification that
cannot be captured by a change in the halo concentration. The decrease
in the total halo mass causes a decrease in the halo mass function of
about 20 per cent. This effect can have important consequences for the
abundance matching technique as well as for most semi-analytic models of
galaxy formation. We provide analytic fitting formulae, derived from
simulations that reproduce the observed baryon fractions, to correct
halo masses and mass functions from DM-only simulations. The effect of
baryon physics (AGN feedback in particular) on cluster number counts is
about as large as changing the cosmology from Wilkinson Microwave
Anisotropy Probe 7 to Planck, even when a moderately high-mass limit of
M500 ≈ 1014 M⊙ is adopted. Thus,
for precision cosmology the effects of baryons must be accounted for.
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