An Isolated Compact Galaxy Triplet

TL;DR

This paper reports the discovery and analysis of an isolated, compact galaxy triplet, highlighting its unique configuration, minimal velocity dispersion, and implications for galaxy evolution theories.

Contribution

It presents the first detection and confirmation of an isolated compact galaxy triplet, emphasizing its well-evolved state and the limitations of current spectral surveys.

Findings

The triplet is highly isolated and compact.

Member galaxies have similar colors and marginal star formation.

The system has very small radial velocity dispersion.

Abstract

We report the discovery of an isolated compact galaxy triplet SDSS J084843.45+164417.3, which is first detected by the LAMOST spectral survey and then confirmed by the spectroscopic observation of the BFOSC of the 2.16 meter telescope. It is found that this triplet is an isolated and extremely compact system, which has an aligned configuration and very small radial velocity dispersion. The member galaxies have similar colors and show marginal star formation activities. These results enhance the opinion that the compact triplets are well-evolved systems rather than the hierarchically forming structures. This occasional discovery reveals the limitations of the fiber spectral redshift surveys in studying such compact system, and declares the necessity of additional observations to complete the current redshift sample.