  We present a multiwavelength study of galaxies around D4UD01, a
spectroscopically confirmed protocluster at z = 3.24 to investigate
environmental trends. 450 galaxies are selected based on Ks band detection with
photometric redshifts (photo-z) at 3.0 < z < 3.4, among which ~ 12% are
classified as quiescent galaxies. The quiescent galaxies are among the most
massive and reddest ones in the entire sample. We identify a large photo-z
galaxy overdensity in the field, which lies close to the previously
spectroscopically confirmed sources of the protocluster. We find that the
quiescent galaxies are largely concentrated in the overdense protocluster
region with a higher quiescent fraction, showing a sign of environmental
quenching. Galaxies in the protocluster are forming faster than the field
counterparts as seen in the stellar mass function, suggesting early and
accelerated mass assembly in the overdense regions. Although weak evidence of
suppressed star-formation is found in the protocluster, the statistics are not
significant enough to draw a definite conclusion. Our work shed light on how
the formation of massive galaxies is affected in the dense region of a
protocluster when the Universe was only 2 Gyr old.

Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics