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Far Infrared Spectroscopy of star-forming galaxies: Expectations for the Herschel Space Observatory

Sangeeta Malhotra
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Abstract

ISO has enabled far-infrared spectroscopy of a variety of galaxies. Using the [CII] (158 micron) and [OI](63 micron) lines, we can characterize the physical conditions in the star-forming ISM. These observations also form the basis of our expectations for what the Herschel Space Observatory will observe for high redshift galaxies. While [CII] is suppressed in ULIRGs and normal galaxies with high dust temperatures, it is stronger than expected in metal poor galaxies by factors of a few. Young galaxies at high redshifts might be expected to be both metal poor and actively star-forming, leading to contrary expectations for the [CII] line strength. The best prediction for [CII] detection is derived by using the observed proportionality between [CII] and mid-IR emission from PAHs. Using the observed [CII]/7 micron ratio and number counts from ISO deep surveys we predict that HSO will be able to detect 100 sources/square-degree in the [CII] line.

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Sangeeta Malhotra. 2001-04-11. Far Infrared Spectroscopy of star-forming galaxies: Expectations for the Herschel Space Observatory. https://arxiv.org/abs/astro-ph/0104198

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