Salle du Conseil de l'Observatoire de Paris, Observatoire de Paris
Gas stripping in galaxy clusters: a new SPH simulation approach
Pavel JACHYM
Observatoires de Prague et de Paris
Résumé :
In this work, we present the results of numerical
simulations of the ram pressure stripping
occurring in galaxy clusters, using tree/SPH N-body code GADGET
(Springel et al. 2001) that we have adapted for two unlike gas
phases: the hot and diffuse intracluster medium (ICM), and the
colder and denser interstellar medium (ISM) . A galaxy moving in a
cluster crosses the ICM and experiences a wind. Local density of
the ICM and orbital velocity of the galaxy determine the effects
of the ram pressure on the galactic ISM. We perform an analysis
of the influence of the galactic, cluster and orbital parameters
on the stripping efficiency, including different galaxy types,
sizes, masses and disk inclinations with respect to the ICM
wind direction, diverse distributions of the cluster ICM, and
various orbital shapes. The goal is in particular to take
into account the finite time for the stripping interaction,
as the galaxy passes quickly through the central region of
the cluster. We compare the results with analytical approximations,
with simple estimates of Gunn \& Gott (1972) formula and with
other recent simulations. Early and late type galaxies in large
or small galaxy clusters show different rates of stripping,
with varying amounts of the reaccreting ISM after the stripping
event. Final mass of the ISM in the disk depends on the
duration of the interaction. We discuss the origin of the ICM
and its large metallicity.
