NGC 6908 , a S0 galaxy situated in direction of NGC 6907 , was only recently recognized as a distinct galaxy , instead of only a part of NGC 6907 .
We present 21 cm radio synthesis observations obtained with the GMRT and optical images and spectroscopy obtained with the Gemini North telescope of this pair of interacting galaxies .
From the radio observations we obtained the velocity field and the H i column density map of the whole region containing the NGC 6907/8 pair , and by means of the Gemini multi-object spectroscopy we obtained high quality photometric images and 5 { \AA } resolution spectra sampling the two galaxies .
By comparing the rotation curve of NGC 6907 obtained from the two opposite sides around the main kinematic axis , we were able to distinguish the normal rotational velocity field from the velocity components produced by the interaction between the two galaxies .
Taking into account the rotational velocity of NGC 6907 and the velocity derived from the absorption lines for NGC 6908 , we verified that the relative velocity between these systems is lower than 60 km s ^ { -1 } .
The emission lines observed in the direction of NGC 6908 , not typical of S0 galaxies , have the same velocity expected for the NGC 6907 rotation curve .
Some emission lines are inside their equivalent absorption lines , reinforcing the idea they were not formed in NGC 6908 .
Finally , the H i profile exhibits details of the interaction , showing three components : one for NGC 6908 , another for the excited gas in the NGC 6907 disk and a last one for the gas with higher relative velocities left behind NGC 6908 by dynamical friction , used to estimate the time when the interaction started in ( 3.4 \pm 0.6 ) \times 10 ^ { 7 } years ago .