A sensitive broadband molecular line survey of the Sagittarius B2(N)
star-forming region has been obtained with the HIFI instrument on the Herschel
Space Observatory, offering the first high-spectral resolution look at this
well-studied source in a wavelength region largely inaccessible from the ground
(625-157 um). From the roughly 8,000 spectral features in the survey, a total
of 72 isotopologues arising from 44 different molecules have been identified,
ranging from light hydrides to complex organics, and arising from a variety of
environments from cold and diffuse to hot and dense gas. We present an LTE
model to the spectral signatures of each molecule, constraining the source
sizes for hot core species with complementary SMA interferometric observations,
and assuming that molecules with related functional group composition are
cospatial. For each molecule, a single model is given to fit all of the
emission and absorption features of that species across the entire 480-1910 GHz
spectral range, accounting for multiple temperature and velocity components
when needed to describe the spectrum. As with other HIFI surveys toward massive
star forming regions, methanol is found to contribute more integrated line
intensity to the spectrum than any other species. We discuss the molecular
abundances derived for the hot core, where the local thermodynamic equilibrium
approximation is generally found to describe the spectrum well, in comparison
to abundances derived for the same molecules in the Orion KL region from a
similar HIFI survey.Comment: Accepted to ApJ. 64 pages, 14 figures. Truncated abstrac
