A Search for Massive Galaxy Population in a Protocluster of LAEs at $z =
  2.39$ near the Radio Galaxy 53W002
  We searched for massive galaxy population in the known large-scale
high-density structure of Lyman$~\alpha$ emitters (LAEs) at $z=2.39$ near the
radio galaxy 53W002 by using $B,~V,~i^\prime,~J,~H,~{\rm{and}}~K_s$-bands
imaging data taken with Suprime-Cam and MOIRCS on the Subaru telescope. We
selected 62 protocluster member candidates by their $JHK_s$-band colors and
Spectral Energy Distribution (SED) fitting analysis ($JHK_s$-selected galaxies)
in our survey field of $70.2~{\rm{arcmin}}^{2}$, and compared their physical
properties estimated from the SED fitting with a comparison sample in the
COSMOS field. We found significant number density excesses for the
$JHK_s$-selected galaxies in the 53W002 field at
$K_s<22.25,~J-K_s>2,~{\rm{or}}~V-K_s>4$. In particular the number density of
the $JHK_s$-selected galaxies with $K_s<22.25~{\rm{and}}~J-K_s>2$ in the 53W002
field is nine times higher than the comparison sample. Most of those with
$K_s<22.25~{\rm{and}}~J-K_s>2$ are massive galaxies with $M_s>10^{11}~M_\odot$,
and their sSFRs of $10^{-11}$--$10^{-10}~\rm{yr^{-1}}$ suggest that the star
formation has not yet stopped completely. We also found a density excess of
quiescent galaxies with
$M_s=5\times10^{10}$--$10^{11}~M_\odot~{\rm{and}}~{\rm{sSFR}}<10^{-11}~\rm{yr^{-1}}$
as well as that of low-mass galaxies with $M_s=10^{9.75}$--$10^{10}~M_\odot$
and various sSFRs. The massive galaxies with $M_s>10^{11}~M_\odot$ are not
located at the density peaks of LAEs, but widely distributed along the similar
direction with the structure of LAEs over $\sim15$--$20$ comoving Mpc. On the
other hand, the quiescent galaxies with ${\rm{sSFR}}<10^{-11}~\rm{yr^{-1}}$
clearly avoid the structure of LAEs. Our results suggest that massive galaxies
also exist in this protocluster discovered by the moderate overdensity of LAEs
and their star formation activities depend on location in the protocluster.
