We investigate numerically the chemodynamical evolution of major disc-disc
galaxy mergers in order to explore the origin of the mass-dependent chemica
l, photometric and spectroscopic properties observed in elliptical galaxies
. We investigate especially the dependence of the fundamental properties on
merger progenitor disc mass (M-d). Three main results are obtained in this
study:
1. More massive (luminous) ellipticals formed by galaxy mergers between mor
e massive spirals have higher metallicity (Z) and thus show redder colours;
the typical metallicity ranges from similar to 1.0 solar abundance (Z simi
lar to 0.02) for ellipticals formed by mergers with M-d = 10(10) M. to simi
lar to 2.0 solar (Z similar to 0.04) for those with M-d = 10(12) M..
2. Both the Mg-2 line index in the central part of ellipticals (R less than
or equal to 0.1 R-e) and the radial gradient of Mg-2 (Delta Mg-2 / Delta l
og R) are more likely to be larger for massive ellipticals. Delta Mg-2 / De
lta log R correlates reasonably well with the central Mg-2 in ellipticals.
For most of the present merger models, ellipticals show a positive radial g
radient of the H-beta line index.
3. Both M/L-B and M/L-K (where M, L-B, and L-K are the total stellar mass o
f galaxy mergers, the B-band and the K-band luminosities, respectively) dep
end on galactic mass in such a way that more massive ellipticals have large
r M/L-B and smaller M/L-K.