Galaxies with 'Rows': A New Catalog

TL;DR

This paper expands the catalog of galaxies with 'rows', analyzes their properties, and discusses formation mechanisms, concluding that such structures are transient and not more common in interacting galaxies, with bars facilitating their formation.

Contribution

It significantly enlarges the catalog of galaxies with 'rows' and provides insights into their formation and evolution mechanisms based on new data and analysis.

Findings

No significant difference in properties between galaxies with and without 'rows'

'Rows' are a transient stage in galaxy evolution

Presence of a stellar bar favors 'rows' formation

Abstract

Galaxies with 'rows' in Vorontsov-Velyaminov's terminology stand out among the variety of spiral galactic patterns. A characteristic feature of such objects is the sequence of straight-line segments that forms the spiral arm. In 2001 A. Chernin and co-authors published a catalog of such galaxies which includes 204 objects from the Palomar Atlas. In this paper, we supplement the catalog with 276 objects based on an analysis of all the galaxies from the New General Catalogue and Index Catalogue. The total number of NGC and IC galaxies with rows is 406, including the objects of Chernin et al. (2001). The use of more recent galaxy images allowed us to detect more 'rows' on average, compared with the catalog of Chernin et al. When comparing the principal galaxy properties we found no significant differences between galaxies with rows and all S-type NGC/IC galaxies.We discuss twomechanisms for the formation of polygonal structures based on numerical gas-dynamic and collisionless N-body calculations, which demonstrate that a spiral pattern with rows is a transient stage in the evolution of galaxies and a system with a powerful spiral structure can pass through this stage. The hypothesis of A. Chernin et al. (2001) that the occurrence frequency of interacting galaxies is twice higher among galaxies with rows is not confirmed for the combined set of 480 galaxies. The presence of a central stellar bar appears to be a favorable factor for the formation of a system of 'rows'.