The HIFI spectral survey of AFGL 2591 (CHESS). II. Summary of the survey

Aims: This paper presents the richness of submillimeter spectral features in the high-mass star forming region AFGL 2591.
Methods: As part of the Chemical Herschel Survey of Star Forming Regions (CHESS) key programme, AFGL 2591 was observed by the Herschel (HIFI) instrument. The spectral survey covered a frequency range from 480 to 1240 GHz as well as single lines from 1267 to 1901 GHz (i.e. CO, HCl, NH₃, OH, and [CII]). Rotational and population diagram methods were used to calculate column densities, excitation temperatures, and the emission extents of the observed molecules associated with AFGL 2591. The analysis was supplemented with several lines from ground-based JCMT spectra.
Results: From the HIFI spectral survey analysis a total of 32 species were identified (including isotopologues). Although the lines are mostly quite weak (∫T_mbdV ~ few K km s^-1), 268 emission and 16 absorption lines were found (excluding blends). Molecular column densities range from 6 × 10¹¹ to 1 × 10¹⁹ cm^-2 and excitation temperatures from 19 to 175 K. Cold (e.g. HCN, H₂S, and NH₃ with temperatures below 70 K) and warm species (e.g. CH₃OH, SO₂) in the protostellar envelope can be distinguished.

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendix A is available in electronic form at http://www.aanda.org