A NEW METHOD OF INVESTIGATION OF THE ORIENTATION OF GALAXIES IN CLUSTERS IN LACK OF INFORMATION ABOUT THEIR MORPHOLOGICAL TYPES

Abstract

The problem of the formation of structures in the universe is one of the most important issues of modern extragalactic astronomy and cosmology. The tool enabling the verification of a particular formation scenario is analysis the spatial orientation of the galaxies from deprojection of their images. Obtaining correct analysis results obliges to take into account the fact that galaxies are oblate spheroids with the real axis ratio depending on the morphological type, which, however, is not given in most of the currently available astronomical data. According to the approach used in the new method of investigation, on the basis of estimated frequencies of occurrence of given morphological types, obtained using sufficiently numerous observational data, simulations are performed, which enable to recognize new angle distributions used in orientation studies. These distributions already contain information on the frequency of the appearance of galaxies of particular morphological types in clusters, allowing for more accurate results of the statistical tests carried out during the analysis. The method is an extension of results developed in Godłowski 2012 and Pajowska et al. 2019.