We obtain the projected mass distributions for two Subaru/Suprime-Cam fields in the southwest region ( r \lower 2.15 pt \hbox { $ \buildrel < \over { \sim } $ } 60 \farcm ) of the Coma cluster ( z = 0.0236 ) by weak lensing analysis and detect eight subclump candidates .
We quantify the contribution of background large-scale structure ( LSS ) on the projected mass distributions using SDSS multi-bands and photometric data , under the assumption of mass-to-light ratio for field galaxies .
We find that one of eight subclump candidates , which is not associated with any member galaxies , is significantly affected by LSS lensing .
The mean projected mass for seven subclumps extracted from the main cluster potential is \langle M _ { { 2 D } } ^ { ( corr ) } \rangle = ( 5.06 \pm 1.30 ) \times 10 ^ { 12 } h ^ { -1 } M _ { \sun } after a LSS correction .
A tangential distortion profile over an ensemble of subclumps is well described by a truncated singular-isothermal sphere model and a truncated NFW model .
A typical truncated radius of subclumps , r _ { t } \simeq 35 ~ { } h ^ { -1 } { kpc } , is derived without assuming any relations between mass and light for member galaxies .
The radius coincides well with the tidal radius , \sim 42 ~ { } h ^ { -1 } { kpc } , of the gravitational force of the main cluster .
Taking into account the incompleteness of data area , a projection effect and spurious lensing peaks , it is expected that mass of cluster substructures account for 19 percent of the virial mass , with 13 percent statistical error .
The mass fraction of cluster substructures is in rough agreement with numerical simulations .