We study statistical intrinsic shape of star-forming BzK galaxies ( sBzK galaxies ) at z \sim 2 in both rest-frame UV and rest-frame optical wavelengths .
The sBzK galaxies are selected down to K _ { AB } = 24.0 mag in the Great Observatories Origins Deep Survey-South ( GOODS-S ) and Subaru-XMM Deep Survey ( SXDS ) fields , where high-resolution images from Hubble Space Telescope are publicly available .
57 % ( 583 ) of all 1028 galaxies in GOODS-S show a single component in the Advanced Camera for Survey ( ACS ) /F850LP image .
As Wide Field Camera ( WFC3 ) /F160W images cover only some part of GOODS-S and SXDS , 724/1028 and 2500/29835 sBzK galaxies in the GOODS-S and SXDS have the WFC3 coverage .
86 % ( 626 ) and 82 % ( 2044 ) of the sBzK galaxies in WFC3/F160W images appear as a single component in the GOODS-S and SXDS , respectively .
Larger fraction of single-component objects in F850LP images represents multiple star-forming regions in galaxies , while they are not so obvious in the F160W image which appears smoother .
Most of the single-component sBzK galaxies show Sérsic indices of n = 0.5 - 2.5 , in agreement with those of local disk galaxies .
Their effective radii are 1.0 - 3.0 kpc and 1.5 - 4.0 kpc in F850LP and F160W images , respectively , regardless of the observed fields .
Stellar surface mass density of the sBzK galaxies is also comparable to that of the local disk galaxies .
However , the intrinsic shape of sBzK galaxies is not a round disk as seen in the local disk galaxies .
By comparing apparent axial ratio ( b / a ) distributions of the sBzK galaxies with those by assuming tri-axial model with axes A > B > C , we found their intrinsic face-on B / A ratios peak at B / A = 0.70 and B / A = 0.77 - 0.79 in the rest-frame UV and optical , respectively and are statistically more bar-like than that of the local disk galaxies .
The intrinsic edge-on C / A ratios in both rest-frame UV and optical wavelengths peak at 0.26 , which is slightly larger than that of the local disk galaxies .
Possible origins of this bar-like structure are bar instability , galaxy interaction , or continuous minor mergers .
Study of galaxy structure evolution in cosmological simulations is desirable to examine the most likely scenario .