Effects of collisions and interactions on star formation in galaxy pairs   in the field
  By using cosmological simulations, we studied the effects of galaxy interactionson the star formation activity in the local Universe. We selected galaxy pairs from the 3D galaxy distribution according to a proximity criterion. The 2D galaxy catalog was constructed by projecting the 3D total galaxy distribution and then selecting projected galaxy pairs. The analysis of the 3D galaxy pair catalog showed that an enhancement of the star formation activity can be statistically correlated with proximity.   The projected galaxy pairs exhibited a similar trend with projected distances and relative radial velocities. However, the star formation enhancement signal is diminished with respect to that of the 3D galaxy pair catalog owing to projection effects and spurious galaxy pairs. Overall, we found that hierarchical scenarios reproduced the observational dependence of star formation activity in pairs on orbital parameters and environment. We also found that geometrical effects due to projection modify the trends more severely than those introduced by spurious pairs. 
Josefa Perez (UNLP-IALP-IAFE), Patricia B. Tissera (IAFE), Diego G.   Lambas (OAC)