Dynamical structure of small bulges reveals their early formation in
  {\Lambda}CDM paradigm
  The {\Lambda} cold dark matter ({\Lambda}CDM) paradigm of galaxy formation
predicts that dense spheroidal stellar structures invariably grow at early
cosmic time. These primordial spheroids evolve toward a virialized dynamical
status as they finally become today's elliptical galaxies and large bulges at
the center of disk galaxies. However, observations reveal that small bulges in
spiral galaxies are common in the nearby universe. The prevailing belief that
all small bulges form at later times from internal processes occurring in the
disk represents a challenge for the {\Lambda}CDM scenario. Notably, the
coevolution of bulges and central supermassive black holes (SMBHs) at early
phases of galaxy evolution is also at stake. However, observations have so far
not provided conclusive evidence against their possible early origin. Here, we
report new observations of small bulges showing that they follow the
mass-velocity dispersion relation expected for virialized systems. Contrary to
previous claims, small bulges bridge the gap between massive ellipticals and
globular clusters. This dynamical picture supports a scenario where systems
over seven orders of magnitude in stellar mass form at early cosmic time. These
results alleviate the tension between {\Lambda}CDM simulations and observations
at galactic scales. We hypothesize that these small bulges are actually the
low-mass descendants of compact objects observed at high redshift, also known
as red nuggets, which are consistently produced in cosmological {\Lambda}CDM
simulations. Therefore, this also suggests that the established coevolution of
SMBHs and large bulges naturally extends to spheroids in the low-mass regime.
