Orientation of galactic disks around Illustris voids

DÁVILA KURBÁN, FEDERICO; LARES, MARCELO; GARCIA LAMBAS, DIEGO

La Serena

Congreso; Reunión anual de la Asociación Argentina de Astronomía; 2018

The alignments of galactic disks with respect to the surrounding structures store information about their formation and dynamical evolution. Cosmic voids are one of the components of the large scale structure of the universe. We define voids as underdense spherical regions with an integrated density of at most 10 the mean density. There is not a clear consensus on whether galactic disks around voids have a preferential orientation with respect to the void-centric direction. Here we present an analysis of the orientations of galactic disks near void walls in the Illustris simulation. We divided the galaxy sample into high and low spin according to a Spin-Mass linear regression. The excess of disks oriented in a given position with respect to the void-centric direction is computed with a novel statistical procedure. We find five voids with radii of about Mpc, out of which three present a significant excess of high-spin disks to reach the void walls at an edge-on position with respect to the void-centric direction. Also, disks with low spin show no significant signal of alignment for any of the voids in the sample.