Ram pressure stripping in a galaxy formation model: a novel numerical approach

T. E. TECCE, ; CORA, S. A.; TISSERA, P. B.; ABADI, M.; LAGOS, C. DEL P.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2010 vol. 408 p. 2008 - 2021

0035-8711

We develop a new numerical approach to describe the action of ram pressure stripping (RPS)within a semi-analytic model of galaxy formation and evolution which works in combinationwith non-radiative hydrodynamical simulations of galaxy clusters. The new feature in ourmethod is the use of the gas particles to obtain the kinematical and thermodynamical propertiesof the intragroup and intracluster medium (ICM). This allows a self-consistent estimation ofthe RPS experienced by satellite galaxies. We find that the ram pressure in the central regionsof clusters increases approximately one order of magnitude between z = 1 and 0, consistentwith the increase in the density of the ICM. The mean ram pressure experienced by galaxieswithin the virial radius increases with decreasing redshift. In clusters with virial massesMvir 1015 h−1M, over 50 per cent of satellite galaxies have experienced ram pressures∼10−11 h−2 dyn cm−2 or higher for z 0.5. In smaller clusters (Mvir 1014 h−1M) themean ram pressures are approximately one order of magnitude lower at all redshifts. RPS hasa strong effect on the cold gas content of galaxies for all cluster masses. At z = 0, over 70 percent of satellite galaxies within the virial radius are completely depleted of cold gas. For themore massive clusters the fraction of depleted galaxies is already established at z 1, whereasfor the smaller clusters this fraction increases appreciably between z = 1 and 0. This indicatesthat the rate at which the cold gas is stripped depends on the virial mass of the host cluster.Compared to our new approach, the use of an analytic profile to describe the ICM results inan overestimation of the ram pressure larger than 50 per cent for z > 0.5.