Estudio estadístico de la actividad de formación estelar en galaxias interactuantes: dependencia con el medio

ALONSO, M. S.; GARCÍA LAMBAS, D.; TISSERA, P.; COLDWELL, G.

La Plata, Argentina

Congreso; Asociación Argentina de Astronomía; 2003

Asociacion Argentina de Astronomía

We analyse the effects of galaxy interactions on star formation in groups and clusters of galaxies with virial masses in the range 1013 - 10 15 M⊙. We find a trend for galaxy-galaxy interactions to be less efficient in high density regions in comparison with galaxies with no close companion. However, the relative projected distance and relative radial velocity thresholds ,rp ~ 25 h-1 kpc and Delta V ~ 100 km s-1, to trigger significant star formation activity are nearly independent of environment. The above results reflect, on one hand, the local nature of star formation induced by tidal interactions and, on the other, the role play by the internal properties of galaxies. The similarity of the distribution of radius and velocity of the pairs normalised to the group virial radius and group mean velocity dispersion is similar to that of other typical group members. We find that galaxy pairs in rich groups are systematically redder and with a lower present-day star formation activity than other group members, suggesting a higher efficiency of galaxy-galaxy interactions in these dense regions in the past.