Ram‐Pressure Stripping of Galaxies in High‐Redshift Clusters and the Influence of Intracluster Medium Heating

We have investigated the ram-pressure stripping of disk galaxies in clustersat various redshifts and in cluster progenitors; the clusters grow up on ahierarchical clustering scenario. We consider a radially infalling galaxy whoseinitial position and velocity are given by a spherical collapse model ofstructure formation. Moreover, since observations show that the intraclustermedium (ICM) of nearby clusters is non-gravitationally heated, we study theeffect of the non-gravitational heating on the ram-pressure stripping. For agiven redshift, we find that ram-pressure stripping has more influence ongalaxies in more massive clusters. On the other hand, for a given mass, it hasmore influence on galaxies in the clusters at higher redshifts. In particular,we predict that in rich clusters at z ~> 1, most of the galaxies are affectedby the ram-pressure stripping. While the non-gravitational heatingsignificantly reduces the influence of ram-pressure stripping on galaxies inclusters with mass smaller than 1-5 10^13 M_sun, it does not affect theinfluence in richer clusters. If the ICM is heated non-gravitationally at z>>1,ram-pressure stripping does not occur at z ~ 1-2 in the progenitors of clustersobserved at 0 ~< z ~< 0.5, because the heat makes the ICM fraction of thecluster progenitors small. On the other hand, if the ICM is heatednon-gravitationally at z ~ 0 for the first time, the ram-pressure strippingoccurs even at z ~ 3. We compare the results with the observations of galaxiesin clusters at various redshifts.Comment: 22 pages, 7 figures, to be published in Ap