A Multiple Dry Merger at z=0.18: Witnessing The Assembly of a Massive
  Elliptical Galaxy
  Mergers of gas-poor galaxies, so-called dry mergers, may play a fundamental
role in the assembly of the most massive galaxies, and therefore, in galaxy
formation theories. Using the SDSS, we have serendipitously discovered a rare
system in the observational and theoretical context, possibly a quintuple dry
merger at low redshift. As a follow-up, we have obtained NOT long-slit spectra
of the group, in order to measure the individual redshifts and gain insight
into its merger fate. Our results show an isolated, low-redshift galaxy group
consisting of massive, quiescent, early-type galaxies, composed of two clumps
(possibly themselves in the process of merging), which we estimate will
hypothetically merge in roughly less than a Gyr. With the possible exception of
the high line-of-sight velocity dispersion, the overall properties of the
system may be comparable to a compact Shakhbazyan group. However, when the
small projected separations and relative mass ratios of the galaxies are taken
into account in cosmological simulations, we find that this system is rather
unique. We hypothesize that this group is a dry merger, whose fate will result
in the assembly of an isolated, massive elliptical galaxy at low redshift.
