Properties of group galaxies at void walls: color, star formation activity and surface brightness

CECCARELLI, M.L.; HERRERA-CAMUS, RODRIGO; GARCÍA LAMBAS, DIEGO; GALAZ, GASPAR; PADILLA, NELSON D.

Mar del Plata

Workshop; 55ª Reunión Anual de la Asociación Argentina de Astronomía; 2012

We study the relative abundance of galaxies at void walls in the SDSS DR7. We focus on galaxies of similar luminosity in equal local density environments. This analysis allows to distinguish the effect of the large-scale environment defined by the void geometry on galaxy. We compare galaxy fractions in the field, and in the void walls; the latter are defined as the volume of void shells of radius equal to that of the void. We find an increment of the fraction blue and active star-forming galaxies at void walls whereas there is a decrement of the fraction of active star-forming LSBGs, in equal mass groups at the void walls and the field. We argue that these results are consistent with a scenario where LSBGs with strong star formation activity at the void walls are fueled by gas from the expanding void regions. This process could lead to LSBG to HSBG transformations.