Schweizer and Seitzer (1998, AJ, 116, 2206)
First, the luminosity functions of young ...
cluster systems are remarkably similar to the mass functions of GMCs
in present-day spiral galaxies (Harris & Pudritz 1994).
Second, ... the radial distribution of the young ... clusters follows
closely the remnant's visual light distribution. This indicates that
the progenitors of the young [massive] clusters experienced the same
violent relaxation as did the disk stars (Schweizer et al. 1996).
This in turn suggests that these progenitors reacted
to the merger
like point masses and were quite compact. The GMCs of the input galaxies
fit the bill, while the more diffuse interstellar gas presumably
experienced significant dissipation and piled up near the center of the
remnant, redistributing itself differently from the stars.