Isolated dwarf galaxies in the local supercluster and its surroundings

TL;DR

This paper identifies 75 isolated late-type dwarf galaxies and 10 spheroidal dwarfs in the local supercluster, providing insights into their properties and implications for galaxy formation theories.

Contribution

It presents a new catalog of isolated dwarf galaxies and compares their properties to those in groups and clusters, highlighting differences in neutral hydrogen content.

Findings

Isolated late-type dwarfs have higher neutral hydrogen mass per luminosity than those in groups.

No significant difference in sizes, luminosities, or internal motions between isolated and group dwarf galaxies.

Detection of isolated dwarf galaxies with exclusively old stars supports cosmological galaxy formation models.

Abstract

We present a list of 75 isolated late-type dwarf galaxies which have no neighbors with a relative radial velocity difference of less than 500 km/s or projected separations within 500 kpc. These were selected from $\sim$2000 dwarf galaxies with radial velocities $V_{LG}<3500$ km/s within the volume of the Local supercluster. In terms of their sizes, luminosities, and the amplitudes of their internal motions, the isolated late-type dwarfs do not differ significantly from gas-rich dwarf galaxies in groups and clusters. However, the median mass of neutral hydrogen per unit luminosity for the isolated dwarf galaxies is two times more than that for the late-type galaxies in groups. We have also identified 10 presumably isolated spheroidal dwarf galaxies. The detection of isolated dwarf galaxies populated exclusively by old stars is of great interest for modern cosmological scenarios of galaxy formation.