Catalog of Nearby Isolated Galaxies in the Volume z<0.01

TL;DR

This paper introduces a catalog of 520 nearby, highly isolated galaxies, analyzing their optical and HI properties, spatial distribution, and signs of interactions, providing insights into galaxy isolation and evolution.

Contribution

The study presents a new catalog of the most isolated nearby galaxies, with detailed analysis of their properties and distribution, highlighting their unique characteristics compared to other galaxy populations.

Findings

Half of the catalog are irregular, bulge-less galaxies.

Median gas-to-star mass ratio exceeds 1.

Galaxies are in regions with significantly lower matter density.

Abstract

We present a catalog of 520 most isolated nearby galaxies with radial velocities V_LG<3500 km/s covering the entire sky. This population of "space orphans" makes up 4.8% among 10900 galaxies with measured radial velocities. We describe the isolation criterion used to select our sample, called the "Local Orphan Galaxies" (LOG), and discuss their basic optical and HI properties. A half of the LOG catalog is occupied by the Sdm, Im and Ir morphological type galaxies without a bulge. The median ratio M_gas/M_star in the LOG galaxies exceeds 1. The distribution of the catalog galaxies on the sky looks uniform with some signatures of a weak clustering on the scale of about 0.5 Mpc. The LOG galaxies are located in the regions where the mean local density of matter is approximately 50 times lower than the mean global density. We indicate a number of LOG galaxies with distorted structures, which may be the consequence of interaction of isolated galaxies with massive dark objects.