The Orientation of Galaxies in Superclusters

Extract

The alignment of galaxies with the main plane of supercluster can contribute to recovering information on the structure origin. The positive result of the preliminary search for galaxy alignment in the Local Supercluster /Flin and Godlowski 1986, hereafter FG/ have stimulated further studies. Following Jaaniste and Saar /1977/, the both parameters, the position angle of the galaxy major axis p and the axial ratio b/a of the galaxy image, were used for the better determination of the actual spatial orientation of the galaxy disc. This approach also permit to consider “face-on” objects, whose discounting leads to obvious incompleteness of the analysed data. Each galaxy has two possible orientations and both were taken into account during calculations. The analysis is perfomed by transforming position angle p and coordinates α, δ of galaxies expressed in the equatorial coordinates into coordinate system connected with each parent supercluster separately, which gives parameters P, l and b respectively. The main supercluster plane should be determined, which resticts the present study to the three superclusters with a known spatial geometry, i.e. LSC /Tully 1982/, Perseus and Coma/A1367 /Chincarini et al. 1983/.