Spectroscopically- and spatially-resolved optical line emission in the Superantennae (IRAS 19254-7245)

TL;DR

This study uses integral field spectroscopy to analyze the optical emission lines in the ULIRG pair IRAS 19254-7245, revealing star formation, AGN activity, and outflows with detailed spatial and spectral resolution.

Contribution

It provides the first spatially and spectrally resolved analysis of optical line emission in this ULIRG pair, distinguishing star formation, AGN, and outflow components.

Findings

Star formation contributes less than 10% to 24 micron flux

Most 24 micron emission is from the AGN in the southern nucleus

Gas consumption time is approximately 1 Gyr

Abstract

We present VIMOS integral field spectroscopic observations of the ultraluminous infrared galaxy (ULIRG) pair IRAS 19254-7245 (the Superantennae). We resolve H alpha, [N II], [O I], and [S II] emission both spatially and spectroscopically and separate the emission into multiple velocity components. We identify spectral line emission characteristic of star formation associated with both galaxies, broad spectral line emission from the nucleus of the southern progenitor, and potential outflows with shock-excited spectral features near both nuclei. We estimate that <~10% of the 24 micron flux density originates from star formation, implying that most of the 24 micron emission originates from the AGN in the southern nucleus. We also measure a gas consumption time of ~1 Gyr, which is consistent with other measurements of ULIRGs.