Faint Companions of Isolated 2MIG Galaxies

TL;DR

This study investigates the presence and characteristics of faint companions around isolated 2MIG galaxies, revealing their properties and implications for galaxy isolation and structure.

Contribution

It provides the first comprehensive analysis of faint companions to isolated 2MIG galaxies, including their luminosities, velocities, and mass-to-light ratios.

Findings

125 objects with 214 neighbors identified

Median companion luminosity is 1/25 of host galaxy

Mass-to-light ratio for ellipticals is 63, for spirals 17

Abstract

We present the results of a search for companions around the isolated galaxies from the 2MIG catalog. Among 3227 2MIG galaxies we detected 125 objects with a total of 214 neighbors having radial velocity differences of Delta V < 500 km/s and projected separations of R_p < 500 kpc relative to the 2MIG galaxies. The median luminosity of the companions is 1/25 of the luminosity of catalog galaxies, which has little effect on the dynamic isolation of the latter. The median ratio of the orbital mass to the K-luminosity determined from 60 companions of E and S0 2MIG galaxies, 63 M_sun/L_sun, is signficantly greater than that found from the spiral galaxy companions (17 M_sun/L_sun). We note that a fraction of 2MIG galaxies with companions may be a part of low-contrast diffuse structures: clouds and filaments.