Molecular Line Survey of CRL 618 from 80 to 276 GHz and Complete Model

Abstract

We present the complete data set, model, and line identification of a survey of the emission fromthe C-rich proto-planetary nebula CRL 618 performed with the IRAM 30 m telescope in the frequencyranges 80.25-115.75 GHz, 131.25-179.25 GHz, and 204.25-275.250 GHz. A selection of lines fromdifferent species has been used in previous works to derive the structure of the source, itsphysical conditions, and the chemical abundances in the different gas regions. In this work, we haveused this information to run a global simulation of the spectrum in order to check the consistencyof the model and to ease the task of line identification. The total number of lines that have acorrespondence in both data and model is ~3100, although quite often in this object many lines blendinto complex features, so that the model, which takes into account line blending, is a key tool atthis stage of the analysis. Of all the lines that we have been able to label, ~55% of them belong tothe different forms of HC 3 N, and ~18% to HC 5 N. The density of remaining unidentified featuresabove the 3 ? limit is only 1 per ~2.1 GHz (74 features), which is unprecedented in the analysis ofthis type of large millimeter-wave line surveys.