A Compendium of Far-Infrared Line and Continuum Emission for 227 Galaxies Observed by the Infrared Space Observatory

TL;DR

This paper presents a comprehensive dataset of far-infrared line and continuum emissions for 227 diverse galaxies observed by ISO, analyzing line ratios and correlations with galaxy properties.

Contribution

It provides the first extensive catalog of far-infrared spectral lines and continuum fluxes for a large, varied galaxy sample, enabling detailed statistical and comparative studies.

Findings

Detection of multiple fine structure lines in diverse galaxy types.

Serendipitous detection of Milky Way [CII] emission and an unidentified line.

Analysis of line ratios reveals trends with galaxy infrared color.

Abstract

Far-infrared line and continuum fluxes are presented for a sample of 227 galaxies observed with the Long Wavelength Spectrometer on the Infrared Space Observatory. The galaxy sample includes normal star-forming systems, starbursts, and active galactic nuclei covering a wide range of colors and morphologies. The dataset spans some 1300 line fluxes, 600 line upper limits, and 800 continuum fluxes. Several fine structure emission lines are detected that arise in either photodissociation or HII regions: [OIII]52um, [NIII]57um, [OI]63um, [OIII]88um, [NII]122um, [OI]145um, and [CII]158um. Molecular lines such as OH at 53um, 79um, 84um, 119um, and 163um, and H2O at 58um, 66um, 75um, 101um, and 108um are also detected in some galaxies. In addition to those lines emitted by the target galaxies, serendipitous detections of Milky Way [CII]158um and an unidentified line near 74um in NGC1068 are also reported. Finally, continuum fluxes at 52um, 57um, 63um, 88um, 122um, 145um, 158um, and 170um are derived for a subset of galaxies in which the far-infrared emission is contained within the ~75" ISO LWS beam. The statistics of this large database of continuum and line fluxes, including trends in line ratios with the far-infrared color and infrared-to-optical ratio, are explored.