IAU Symposium Abstract S186-064P
Stellar Population of Dissipative Merger
Y. Shioya1, K.Bekki2
1 Center for Interdisciplinary Research, Tohoku Univ.
2 Astronomical Institute, Tohoku Univ. <email@example.com>
For the formation of elliptical galaxies, two dominant and competing
scenarios are proposed. One is the protogalactic gravitational collapse
and the other is merger of disk galaxies (merger hypothesis).
As already known, it is difficult to reproduce the color - luminosity
relation and the metallicity gradient observed for elliptical galaxies
in the framework of stellar disk mergers. However, in general, disk
galaxies include gaseous component and it is considered that the gas
mass fractions of disk galaxies in the early universe is larger than
those in our neighborhood. Thus, we numerically investigate chemical
and dynamical evolution of gas-rich galaxy mergers in a self-consistent
manner. We especially investigate the dependence of the nature of
stellar population of merger remnants on the rapidity of gas consumption
by star formation during merging. We found that galaxy mergers with
more (less) rapid gas consumption by star formation show a larger
(smaller) degree of metal enrichment and a shallower (steeper)
metallicity gradient. We discuss tha validity of merger hypothesis
based on our results.