The fate of high-redshift massive compact galaxies
  Massive high-redshift quiescent compact galaxies (nicknamed red nuggets) have
been traditionally connected to present-day elliptical galaxies, often
overlooking the relationships that they may have with other galaxy types. We
use large bulge-disk decomposition catalogues based on the Sloan Digital Sky
Survey (SDSS) to check the hypothesis that red nuggets have survived as compact
cores embedded inside the haloes or disks of present-day massive galaxies. In
this study, we designate a "compact core" as the bulge component that satisfies
a prescribed compactness criterion. Photometric and dynamic mass-size and
mass-density relations are used to show that, in the inner regions of galaxies
at z ~ 0.1, there are "abundant" compact cores matching the peculiar properties
of the red nuggets, an abundance comparable to that of red nuggets at z ~ 1.5.
Furthermore, the morphology distribution of the present-day galaxies hosting
compact cores is used to demonstrate that, in addition to the standard channel
connecting red nuggets with elliptical galaxies, a comparable fraction of red
nuggets might have ended up embedded in disks. This result generalises the
inside-out formation scenario; present-day massive galaxies can begin as dense
spheroidal cores (red nuggets), around which either a spheroidal halo or a disk
are formed later.
