Description |
Luminous Infrared Galaxies (LIRGs; having LIR > 10^11 Lsun), emit a significant fraction of their bolometric luminosity in the far-infrared and are a mixture of single galaxies, interacting systems and advanced mergers, exhibiting enhanced star formation rates and a higher fraction of Active Galactic Nuclei (AGN) compared to less luminous galaxies. With the Great Observatories All-sky LIRG Survey (GOALS), we are measuring the properties of a large, complete sample of 202 low-redshift LIRGs across the electromagnetic spectrum using Spitzer, HST, Chandra, GALEX and a number of ground-based observatories. Here, we propose to measure the CII 157.7, OI 63.2 and OIII 88 micron far-infrared emission lines and the OH 79 micron absorption feature in the GOALS sample with the PACS on the Herschel Space Observatory. We will target 154 LIRGs in CII, OI, and OH and 66 LIRGs in OIII for a total requested time of 166.9 hrs. The PACS data will allow us to penetrate the dust and measure the spatial distribution, dynamics and overall energy budgets in a large sample of LIRGs at low redshift for the first time. In addition to providing a measure of the physical conditions in the warm, neutral and ionized interstellar medium (ISM) in LIRGs, these data will allow us to establish a precise, quantitative FIR-based measure of the star formation rate that can be used across a wide range of galactic luminosities, even in the presence of powerful AGN. GOALS, with its rich ancillary dataset that covers X-ray through millimeter wavelengths, provides the perfect sample for this study. Our proposed observations will greatly extend the work started with ISO, and lay the foundation for high-redshift galactic studies with future facilities (e.g., ALMA) that will target the FIR and sub-mm spectral regions over the next decade. |