The nature of small groups of galaxies in the Local Supercluster

Abstract

view Abstract Citations (57) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The nature of small groups of galaxies in the Local Supercluster. Turner, E. L. ; Sargent, W. L. W. Abstract We examine the nature of the 54 groups of galaxies in the Local Supercluster (LSC) given in de Vaucouleurs's list. We find from three independent tests that the LSC contains two distinct kinds of groups. Only 13 of the 44 groups for which good data are available are likely to be bound systems. The rest are probably loose aggregates of neighboring field galaxies which are expanding apart in the Hubble flow in the manner proposed by Gott, Wrixon, and Wannier. We show that the 13 groups which pass our tests contain a higher proportion of early-type galaxies and have a significantly lower median virial mass discrepancy than those which fail one or more tests. The statistical application of the virial theorem to the local galaxies by Geller and Peebles is considered. We conclude that the existence of a large number of unbound density enhancements modifies their results. The statistics of the angular separations of pairs of galaxies computed by Geller and Peebles are shown to be consistent with our estimate of the number of bound and unbound groups. Publication: The Astrophysical Journal Pub Date: December 1974 DOI: 10.1086/153277 Bibcode: 1974ApJ...194..587T Keywords: Galactic Clusters; Galactic Structure; Mass Ratios; Virial Theorem; Celestial Mechanics; Elliptical Galaxies; Galactic Evolution; Spiral Galaxies; Statistical Analysis; Astrophysics full text sources ADS |