Morphological dependence in the spatial orientations of Local Supercluster galaxies

Abstract

Abstract.We have compiled a database of 4073 morphologically identified galaxies with radial velocity <3000 km s −1 and examined the alignments of the spin vectors of these galaxies in the Local Supercluster (LSC). Our aim is to test the morphological dependence of galaxy orientation. The "position angle -inclination" method is used to find the polar and azimuthal angles of the galaxy rotation axes. The spatial isotropic distribution is assumed to examine the non-random effects. We have carried out chi-square, Fourier, and auto correlation tests to examine non-random effects in the distributions of the polar and azimuthal angles of the galaxy rotation axes. We suspect that the orientations of galaxies in the LSC could be closely related to galactic morphology. The spiral galaxies exhibit anisotropy although not at a very high significance level. It is found that the spin vector orientations of the spiral galaxies in the LSC tend to lie perpendicular to the LSC plane. No preferred orientation is found in the spin vector orientations of barred spiral and irregular galaxies. The orientations of early-type and late-type spirals and barred spirals are discussed.

Spiral Galaxies as Chiral Objects?

“…Another interesting result is reported by Aryal and Saurer (2005). These authors analysed the distribution of angular momentum of 2280 S galaxies and 1162 SB galaxies in the Local Supercluster.…”

“…This feature of a spiral galaxy can be considered genetic in the sense that it is the original angular momentum of the protogalaxy that gives rise to the spiral structure which permanently remains a characteristic of the system. Joined to the fact that, observations almost always reveal trailing arms, (Sugai and Iye, 1991;Hu, 1998;Aryal andSaurer, 2004, 2005;Kashikawa and Okamura, 1992) it seems that chiral asymmetry is present in spiral galaxies and only one modality is favoured likewise in the case of aminoacids and neutrinos (both left-handed).…”

Preferred alignments of angular momentum vectors of galaxies in six dynamically unstable Abell clusters

“…The expected isotropic distribution curves for angular momentum vectors and its projections are determined by performing a random simulation (Aryal & Saurer 2000). The observed distributions are compared with the expected using various statistical tests.…”

“…We perform random simulation method proposed by Aryal & Saurer (2000) in order to find expected isotropic distribution curves (θ and φ) by removing above mentioned selection effects. We apply cosmological principle by assuming isotropic distribution of angular momentum vectors of 10 7 virtual galaxies and use the formulae (1) and (2) in the random simulation.…”

Astrophysics in 2005

“…Yes, say the data (Aryal & Saurer 2005, and a handful of additional index-year papers). And, curiously, both are predicted, or, anyhow, calculated (Bailin & Steinmetz 2005).…”