We report detailed evidence for : multiple merger , extended massive star formation , galactic–wind and circular/non-circular motions in the luminous infrared galaxy NGC 3256 .
Based on observation of high resolution imaging ( obtained at HST and ESO–NTT ) , and extensive kinematical/spectroscopic data ( more than 1000 spectra , collected at Bosque Alegre , CASLEO , CTIO and IUE Observatories ) .

We find in a detailed morphological study ( at \sim 15 pc resolution ) that the extended massive star formation process , detected previously in NGC 3256 shows : ( i ) extended triple asymmetrical spiral arms structure ( r \sim 5 kpc ) ; and ( ii ) the spiral arms emanate from three different nuclei .
The main optical nucleus shows a small spiral–disk ( r \sim 500 pc ) which is a continuation of the external one and reach the very nucleus .
And this very nucleus shows blue elongate structure ( 63 pc \times 30 pc ) , and luminous blue star cluster properties .
We discuss this complex morphology , in the framework of an extended massive star formation driven by multiple merger process ( Hernquist et al. , Taniguchi et al. ’ s models ) .

We study the kinematics of this system and present a detailed H \alpha velocity field for the central region ( 40 ^ { \prime \prime } \times 40 ^ { \prime \prime } ; r _ { max } \sim 30 ^ { \prime \prime } \sim 5 kpc ) ; with a spatial resolution of 1 ^ { \prime \prime } , and errors of \pm 15 km s ^ { -1 } .
The color and isovelocity maps show mainly : ( i ) a clear kinematical center of circular motion with “ spider ” shape and located between the main optical nucleus and the close ( 5 ^ { \prime \prime } ) mid-IR knot/nucleus ; ( ii ) non–circular motions in the external parts .
In the main optical nucleus we found a clear “ outflow component ” associated to galactic–winds and a “ inflow radial motion ” ( in the spiral-disk nuclear structure , r \sim 700 pc ) .
In addition , we detected the outflow component in the central and external regions ( r \leq 5-6 kpc ) , with a very wide opening angle \theta = 140 ^ { \circ } .
We found that the mean value of the inflow region ( at PA \sim 80 ^ { \circ } ) is practically perpendicular to the axis of the bipolar outflow ( at PA \sim 160 ^ { \circ } ) .
Our optical spectroscopic data cube show that the three asymmetrical spiral arms have no kinematical relation to each other .

We analyze in detail the physical conditions in the giant H ii regions located in the asymmetric spiral arms , the two main optical knots/ nuclei , and the outflow component ( using long slit spectroscopy , plus standard models of fotoionization , shocks and starburst ) .
We present four detailed emission line ratios ( N ii /H \alpha , S ii /H \alpha , S ii /S ii ) and FWHM ( H \alpha ) maps for the central region ( 30 ^ { \prime \prime } \times 30 ^ { \prime \prime } ; r _ { max } \sim 22 ^ { \prime \prime } \sim 4 kpc ) , with a spatial resolution of 1 ^ { \prime \prime } .
We found that the massive star formation is extended from the very nucleus to the end of the tidal tails : i.e. , from r \sim 15 pc to \sim 40 kpc .
In particular , in the central region ( r \sim 5–6 kpc ) we detected that the nuclear starburst and the extended giant H ii regions ( in the spiral arms ) have very similar properties , i.e. , high metallicity and low ionization spectra , with : T _ { eff } = 35000 ^ { \circ } K , solar abundance , a range of T _ { e } \sim 6000–7000 ^ { \circ } K and N _ { e } \sim 100–1000 cm ^ { -3 } .
These results are in excellent agreement with the global IR emission lines studies made by Joseph and collaborators .
In addition , the nuclear and extended outflow shows properties typical of galactic–wind/shocks , associated to the nuclear starburst .
And , we suggest that the interaction between dynamical effects , the galactic–wind ( outflow ) , low-energy cosmic rays , and the molecular+ionized gas ( probably in the inflow phase ) could be the possible mechanism that generate the “ similar extended properties in the massive star formation , at scale of 5-6 kpc ! ” .

In conclusion , these results suggest that NGC 3256 is the product of a multiple merger , which generated an extended massive star formation process with an associated galactic–wind plus an inflow ( mainly , in the nuclear region ) .
Finally , we have also studied the presence of the close merger/interacting systems NGC 3256C ( at \sim 150 kpc , and \Delta V \sim 200 km s ^ { -1 } ) , and NGC 3256A , plus the possible association between the NGC 3256 and 3263 groups of galaxies .
Furthermore , we analyze for NGC 3256 the possible evolution from luminous IR galaxy to QSOs , elliptical , cD , or radio galaxy ( Toomre , Schweizer , Joseph et al. , Sanders et al. , Terlevich et al. ’ s models ) , where the powerful galactic–wind and the relation between mergers and extreme dusty-starburst play a main role in this evolutive process ( Rieke et al. , Joseph et al. , Heckman et al. , Lipari et al. ’ s hypothesis ) , and probably in the formation and evolution of galaxies .