Open AccessEnhanced mergers of galaxies in low‐redshift clusters
Author(s) -
Moss C.
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.11000.x
Subject(s) - physics , astrophysics , galaxy cluster , brightest cluster galaxy , population , astronomy , cluster (spacecraft) , galaxy , redshift , galaxy merger , virial theorem , velocity dispersion , demography , sociology , computer science , programming language
An ensemble cluster has been formed from a data set comprising a complete magnitude‐limited sample of 680 giant galaxies ( M 0 B ≲−19) in eight low‐redshift clusters, normalized by the velocity dispersions and virial radii for the early‐type cluster populations. Distinct galaxy populations have been identified, including an infall population. A majority (50–70 per cent or greater) of the infall population are found to be in interacting or merging systems characterized by slow gravitational encounters. The observed enhancement of galaxy–galaxy encounters in the infall population compared to the field can be explained by gravitational shocking. It is shown that disc galaxy mergers in the infall population integrated over the estimated lifetime of the cluster (∼10 Gyr) can readily account for the present cluster S0 population.