A large moving group within the Lower Centaurus Crux association
  Scorpius-Centaurus is the nearest OB association and its hundreds of members
were divided into sub-groups, including Lower Centaurus Crux. Here we study the
dynamics of the Lower Centaurus Crux area stellar content. We report the
revelation of a large moving group containing more than 1800 intermediate- and
low-mass young stellar objects and brown dwarfs, that escaped identification
until Gaia DR2 allowed to perform a kinematic and photometric selection. We
investigate the stellar and substellar content of this moving group using the
Gaia DR2 astrometric and photometric measurements. The median distance of the
members is 114.5 pc and 80% lie between 102 and 135pc from the Sun. Our new
members cover a mass range of 5M$_\odot$ to 0.02M$_\odot$, and add up to a
total mass of about 700M$_\odot$. The present-day mass function follows a
log-normal law with m$_c$ = 0.22 M$_\odot$ and $\sigma$ = 0.64. We find more
than 200 brown dwarfs in our sample. The star formation rate had its maximum of
$8\times10^{-5}\rm M_\odot yr^{-1}$ at about 9Myr ago, We grouped the new
members in four denser subgroups, which s have increasing age from 7 to 10Myr,
surrounded by "free-floating" young stars with mixed ages. Our isochronal ages,
now based on accurate parallaxes, are compatible with several earlier studies
of the region. The whole complex is presently expanding, and the expansion
started between 8 to 10Myr ago. Two hundred members show infrared excess
compatible with circumstellar disks from full to debris disks. This discovery
provides a large sample of nearby young stellar and sub-stellar objects for
disk and exoplanet studies.
