Mergers of galaxies play an important role in the evolution of galaxies. If merging is at work during the lifetime of galaxies, then the space density, mass, luminosity and morphology of galaxies must change with epoch making the evolution of the merger ra te with redshift a key observable that can be used to test galaxy formation models. Time-scales associated with merging are not straightforward to constraint since there is a considerable uncertainty in any transformation from an "instantaneous" merger rat e (computed directly from observation at a given look-back time) to a "global" merger rate that indicates the likelihood for a galaxy to experience merging from any epoch to the present. Transforming the observed merger rate fraction into a merger rate req uires knowledge of the average time-scale over which a merger is completed, i.e. time over which morphological traces of the merger are gone at the resolution at which one is observing a particular sample. An upper limit for this time-scale is 400 Myr to 1 Gyr.The purpose of this project is to restrain the uncertaintes in the value of this time-scale through the detailed observations of the kinematics of particular interacting pairs at different redshifts and their numerical modelling. Observations of inter acting pairs will encompass distant galaxies using the new 3D multi-object spectroscopy instrument GIRAFFE at ESO's Very Large Telescope (VLT) as well as nearby interacting pairs using the scanning interferometer at ESO's 3.6 m telescope, the MOS-FP on the CFHT and the PUMA scanning interferometer at OAN-SPM. Simulations will be done using N-body and SPH numerical codes and applying strict morphological and kinematical constraints issued from observations. Models will be left to evolve in order to compute t he time-scale over which the merging process is completed. A classification of kinematics of galaxies will be established in order to facilitate the analysis between observations and numerical models.
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