English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present a comprehensive analysis of a broad band spectral line survey ofthe Orion Kleinmann-Low nebula (Orion KL), one of the most chemically richregions in the Galaxy, using the HIFI instrument on board the Herschel SpaceObservatory. This survey spans a frequency range from 480 to 1907 GHz at aresolution of 1.1 MHz. These observations thus encompass the largest spectralcoverage ever obtained toward this high-mass star-forming region in the sub-mmwith high spectral resolution, and include frequencies $>$ 1 THz where theEarth's atmosphere prevents observations from the ground. In all, we detectemission from 39 molecules (79 isotopologues). Combining this dataset withground based mm spectroscopy obtained with the IRAM 30 m telescope, we modelthe molecular emission from the mm to the far-IR using the XCLASS program whichassumes local thermodynamic equilibrium (LTE). Several molecules are alsomodeled with the MADEX non-LTE code. Because of the wide frequency coverage,our models are constrained by transitions over an unprecedented range inexcitation energy. A reduced $\chi^{2}$ analysis indicates that models for mostspecies reproduce the observed emission well. In particular, most complexorganics are well fit by LTE implying gas densities are high ($>$10$^6$cm$^{-3}$) and excitation temperatures and column densities are wellconstrained. Molecular abundances are computed using H$_{2}$ column densitiesalso derived from the HIFI survey. The distribution of rotation temperatures,$T_{\rm rot}$, for molecules detected toward the hot core is significantlywider than the compact ridge, plateau, and extended ridge $T_{\rm rot}$distributions, indicating the hot core has the most complex thermal structure.

Herschel observations of EXtra-Ordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL I. Methods