Galaxy Luminosity Function of Dynamically Young Abell 119 Cluster:
  Probing the Cluster Assembly
  We present the galaxy luminosity function (LF) of the Abell 119 cluster down
to $M_r\sim-14$ mag based on deep images in the $u$-, $g$-, and $r$-bands taken
by using MOSAIC II CCD mounted on the Blanco 4m telescope at the CTIO. The
cluster membership was accurately determined based on the radial velocity
information as well as on the color-magnitude relation for bright galaxies and
the scaling relation for faint galaxies. The overall LF exhibits a bimodal
behavior with a distinct dip at $r\sim18.5$ mag ($M_r\sim-17.8$ mag), which is
more appropriately described by a two-component function. The shape of the LF
strongly depends on the cluster-centric distance and on the local galaxy
density. The LF of galaxies in the outer, low-density region exhibits a steeper
slope and more prominent dip compared with that of counterparts in the inner,
high-density region. We found evidence for a substructure in the projected
galaxy distribution in which several overdense regions in the Abell 119 cluster
appear to be closely associated with the surrounding, possible filamentary
structure. The combined LF of the overdense regions exhibits a two-component
function with a distinct dip, while the LF of the central region is well
described by a single Schechter function. We suggest that, in the context of
the hierarchical cluster formation scenario, the observed overdense regions are
the relics of galaxy groups, retaining their two-component LFs with a dip,
which acquired their shapes through galaxy merging process in group
environments, before they fall into a cluster.
