Interacting galaxies provide us with an excellent laboratory for studying a number of physical phenomena associated with these processes .
In this paper , we present a spectroscopic and kinematic analysis of the interacting galaxy NGC 4656 and its companion Tidal Dwarf Galaxy ( TDG ) candidate , NGC 4656UV .
Using Fabry-Perot and GMOS multi-slit data , we investigated the possible origin of NGC 4656UV .
We found that NGC 4656UV has a low metallicity ( 12+log ( O/H ) \sim 8.2 ) and it follows the mass-metallicity relation ( MZR ) for normal dwarf galaxies .
For NGC 4656 , we estimated a flat oxygen abundance gradient of \beta = -0.027 \pm 0.029 dex kpc ^ { -1 } , which suggests the presence of gas flows induced by gravitational interactions .
By analysing radial velocity profiles and by fitting a kinematic model of the observed velocity field , we confirm the literature result that NGC 4656 consists of one single body instead of two objects .
We estimated a dynamical mass of 6.8 ^ { 1.8 } _ { -0.6 } \times 10 ^ { 9 } M _ { \sun } and R of 12.1 kpc from the kinematic model of NGC 4656 .
Although the observed velocity field is dominated by rotation at large scales ( V _ { max } / \sigma \gtrsim 2.8 ) , important non-rotational motions are present at small scales .
Based on these new results , and on previously published information , we propose that NGC 4656 and 4656UV are a pair of interacting galaxies .
NGC 4656UV is a companion of NGC 4656 and it does not have a tidal origin .
The interaction between the two could have triggered the star formation in NGC 4656UV and increased the star formation in the northeast side of NGC 4656 .