Spatial distribution of galaxies in the Puppis region

Abstract

We determine the spatial distribution of the galaxies located behind the part of the zone of avoidance of the Milky Way defined by 220° < l < 260°, |b| < 20°, δ ≤ 0°, up to a distance of 8000 km s -1 . We use a sample of 369 galaxies with measured redshifts, of which 97 have been detected with the Nancay radio telescope. We show that our sample can be considered to be complete in apparent diameter down to 1.9 arcmin, a property that allows us to correct the density of galaxies for the loss of objects with distance. We then search for groups of galaxies using a companionship method and find 12 groups with at least five members, of which five are new. The members of one group are H I deficient by a factor of 1.6 on average. The method is then used to search for large structures and allows us to characterize the Puppis wall at 1400 < V 0 < 2600 km s -1 ; it is 30 Mpc long, with the main axis being parallel to the sky plane, and it connects the Antlia cluster to the Fornax cluster through the zone of avoidance. The density of galaxies in the wall is approximately 20 times the general density of galaxies, i.e. half that observed in the densest part of the Pisces-Perseus supercluster. No internal motions are found along the line of sight, indicating that the Puppis wall has not yet collapsed.