Ionized gas outflow in the isolated S0 galaxy NGC 4460

TL;DR

This study investigates ionized gas outflows in the isolated S0 galaxy NGC 4460, revealing star formation-driven winds concentrated in the galaxy's center and discussing their implications for galaxy evolution.

Contribution

It provides detailed analysis of gas outflows in NGC 4460, highlighting the role of central star formation and comparing wind parameters with other isolated galaxies.

Findings

Ionized gas outflow driven by central star formation.

Outflow velocity and energy are smaller than in NGC 253.

Feeding of isolated galaxies by intergalactic gas is steady over time.

Abstract

We use integral-field and long-slit spectroscopy to study the bright extended nebulosity discovered in the isolated lenticular galaxy NGC 4460 during a recent H-alpha survey of nearby galaxies. An analysis of archival SDSS, GALEX, and HST images indicates that current star formation is entirely concentrated in the central kiloparsec of the galaxy disc. The observed ionized gas parameters (morphology, kinematics and ionization state) can be explained by a gas outflow above the plane of the galaxy caused by a star formation in the circumnuclear region. Galactic wind parameters in NGC 4460: outflow velocity, total kinetic energy - are several times smaller comparing with the known galactic wind in NGC 253, which is explained substantially lower total star formation rate. We discuss the cause of the star formation processes in NGC 4460 and in two other known isolated S0 and E galaxies of the Local volume: NGC 404 and NGC 855. We provide evidence suggesting that feeding of isolated galaxies by intergalactic gas on a cosmological time scale is a steady process without significant variations.