The Hubble sequence: just a vestige of merger events?
  Abr: We investigate whether the Hubble sequence can be reproduced by the
relics of merger events. We verify that, at zmed=0.65, the abundant population
of anomalous starbursts is mainly linked to the local spirals. Their
morphologies are dominated by young stars and are related to their ionised-gas
kinematics. We show that both morphologies and kinematics can be reproduced by
using gas modelling from Barnes' (2002) study of major mergers. Using our
modelling to estimate the gas-to-stars transformation during a merger, we
identify the gas fraction in the progenitors to be generally above 50%. All
distant and massive starbursts can be distributed along a temporal sequence
from the first passage to the nuclei fusion and then to the disk rebuilding
phase. It confirms that the rebuilding spiral disk scenario is possibly an
important channel for the formation of present-day disks in spirals. Because
half of the present-day spirals had peculiar morphologies and anomalous
kinematics at zmed=0.65, they could indeed be in major mergers phases 6 Gyrs
ago, and almost all at z~1. It is time now to study in detail the formation of
spiral disks and of their substructures, including bulge, disks, arms, bars,
rings that may mainly originate from instabilities created during the last
major merger.
