Kinematics and Origin of Gas in the Disk Galaxy NGC 2655

TL;DR

This study analyzes the distribution, excitation, and kinematics of ionized gas in galaxy NGC 2655, revealing a large gaseous disk with regular rotation and remnants of a recent minor merger event.

Contribution

It provides new observational data and a combined analysis showing the coexistence of a stable gaseous disk and recent merger remnants in NGC 2655.

Findings

Identification of a large gaseous disk with regular circular rotation.

Detection of remnants from a recent minor merger event.

Evidence of complex gas dynamics indicating multiple origins.

Abstract

The new observational data concerning distribution, excitation, and kinematics of the ionized gas in the giant early-type disk galaxy NGC 2655 obtained at the 6m telescope of the Special Astrophysical Observatory (SAO RAS) and at the 2.5m telescope of the Caucasian Mountain Observatory of the Sternberg Astronomical Institute (CMO SAI MSU) are presented in this work. The joint analysis of these and earlier spectral observations has allowed us to make a conclusion about multiple nature of the gas in NGC 2655. Together with a proper large gaseous disk experiencing regular circular rotation in the equatorial plane of the stellar potential of the galaxy for billions years, we observe also remnants of a merged small satellite having striked the central part of NGC 2655 almost vertically for some 10 million years ago.