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Paper: The Infrared Lines of OH: Diagnostics of Molecular Cloud Conditions in Infrared Bright Galaxies
Volume: 320, The Neutral ISM in Starburst Galaxies
Page: 49
Authors: Smith, H.; Gonzalez-Alfonso, E.; Fischer, J.; Ashby, M.; Dudley, C.; Spinoglio, L.
Abstract: ISO detected 9 of the 15 far-IR lines of OH that arise between the molecule's lowest 8 rotational levels. The lines were seen, sometimes in emission and sometimes in absorption, in a wide variety of galactic and extragalactic objects ranging from AGB stars to molecular clouds in AGN and LIRGs. This set of OH lines provides an important diagnostic for many reasons: they span a wide wavelength range (from 28.9μm to 163.2μm); the transitions have fast radiative rates; the abundance of OH is relatively high; the IR continuum plays an important role as a pump; the contribution from shocks is relatively minor; and, not least, the strong cm-wave radiation from OH allows comparison with VLBI datasets. OH plays a key role in the chemistry of the ISM. We have used montecarlo and non-local radiative transfer codes to analyze the spectra of a number of LIRGs with excellent success., Other detected lines in the ISO spectra, including those from H2O, CH, NH3, CO, [CII] and [OI], are also modeled by the codes, as is the continuum.
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