EDP Sciences
Free access
Volume 479, Number 2, February IV 2008
Page(s) 397 - 407
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20077810

A&A 479, 397-407 (2008)
DOI: 10.1051/0004-6361:20077810

Coexistence of chiral symmetry restoration and random orientation of galaxies

B. Aryal1, 2, S. Paudel2, and W. Saurer1

1  Institut für Astrophysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
    e-mail: [binil.aryal;walter.saurer]@uibk.ac.at
2  Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal
    e-mail: sanjpaudel@yahoo.com

(Received 8 May 2007 / Accepted 21 November 2007)

We studied the chiral symmetry restoration and the spatial orientation of 2288 spiral and spiral barred galaxies that have radial velocities (RV) less than 5000 km s-1. A random direction of the rotation of galaxies is assumed in order to classify the structural modes. The distribution of spin vector and spin vector projections of leading and trailing arm galaxies in the total sample and subsamples are studied. We use chi-square, auto-correlation and Fourier tests in order to discriminate the preferred alignments from the random alignments. A good correlation between the random alignment and the chiral symmetry is noticed in the Local Supercluster (RV < 3000 km s-1) and in galaxies nearby the Local Supercluster (3000 < RV (km s-1) $\leq$ 5000). Spiral galaxies show a similar result. The barred spirals show an opposite trend to that observed for the spirals. Nearby the Local Supercluster, we noticed a preferred spatial alignment and non-chiral property in the leading and trailing arm spiral barred galaxies. Our result predicts that the progressive loss of chirality might have some connection with the rotationally supported (spirals, barred spirals) and randomized (lenticulars, ellipticals) systems. Thus, we suspect that the dynamical processes in the cluster evolution give rise to a dynamical loss of chirality.

Key words: Galaxy: formation -- galaxies: statistics -- Galaxy: evolution -- Galaxy: structure

© ESO 2008