Galaxy formation at z > 3 revealed by narrow-band selected [OIII]
  emission line galaxies
  We present the physical properties of [OIII] emission line galaxies at z>3 as
the tracers of active galaxies at 1Gyr before the peak epoch at z~2. We have
performed deep narrow-band imaging surveys in the Subaru/XMM-Newton Deep Survey
Field with MOIRCS on the Subaru Telescope and have constructed coherent samples
of 34 [OIII] emitters at z=3.2 and 3.6, as well as 107 H$\alpha$ emitters at
z=2.2 and 2.5. We investigate their basic physical quantities, such as stellar
masses, star formation rates (SFRs), and sizes using the publicly available
multi-wavelength data and high resolution images by the Hubble Space Telescope.
The stellar masses and SFRs show a clear correlation known as the "main
sequence" of star-forming galaxies. It is found that the location of the main
sequence of the [OIII] emitters at z=3.2 and 3.6 is almost identical to that of
the H$\alpha$ emitters at z=2.2 and 2.5. Also, we investigate their mass-size
relation and find that the relation does not change between the two epochs.
When we assume that the star-forming galaxies at z=3.2 grow simply along the
same main sequence down to z=2.2, galaxies with $M_* = 10^{9}$-$10^{11}
M_{\odot}$ increase their stellar masses significantly by a factor of 10-2.
They climb up the main sequence, and their star formation rates also increase a
lot as their stellar masses grow. This indicates that star formation activities
of galaxies are accelerated from z>3 towards the peak epoch of galaxy formation
at z~2.
