The Bridge Effect of Void Filaments

Cosmic filaments play a role of bridges along which matter and gas accrete onto galaxies to trigger star formation and feed central black holes. Here we explore the correlations between the intrinsic properties of void galaxies and the linearity RL of void filaments (degree of filament’s straightness). We focus on void regions since the bridge effect of filaments should be most conspicuous in the pristine underdense regions like voids. Analyzing the Millennium-Run semi-analytic galaxy catalogue, we identify void filaments consisting of more than four galaxies (three edges) and calculate the means of central black hole mass, star formation rate, and stellar mass as a function of RL. It is shown that the void galaxies constituting more straight filaments tend to have higher luminosity, more massive central black holes and higher star formation rate. Among the three properties, the central black hole mass is most strongly correlated with RL. It is also shown that the dark halos constituting straight filaments tend to have similar masses. Our results suggest that the fuel-supply for central black holes and star formation of void galaxies occurs most efficiently along straight void filaments whose potential wells are generated by similar-mass dark halos.