Broadband analysis techniques for Herschel/HIFI spectral surveys of chemically rich star-forming regions

摘要

The Heterodyne Instrument for the Far Infrared (HIFI) aboard the HerschelSpace Observatory has acquired high-resolution broadband molecular spectra ofstar-forming regions in a wavelength range that is mostly inaccessible fromground-based astronomical observatories. These spectral surveys provide newinsight into the chemical composition and physical properties of molecularclouds. In this manuscript, we present initial results from the HIFI spectralsurvey of the Sagittarius B2(N) molecular cloud, which contains spectralfeatures assigned to at least 40 different molecules in a range of physicalenvironments. While extensive line blending is observed due to the chemicalcomplexity of this region, reliable molecular line identifications can be made,down to the noise floor, due to the large number of transitions detected foreach species in the 1.2 THz survey bandwidth. This allows for the extraction ofnew weakly emitting species from the line forest. These HIFI surveys will be aninvaluable archival resource for future investigations into interstellarchemistry.