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The computer-accessible Cologne Database for Molecular Spectroscopy (CDMS) contains a catalog of radio frequency and microwave to far-infrared spectral lines of atomic and molecular species that (may) occur in the interstellar or circumstellar medium or in planetary atmospheres. The catalog is continuously updated and is primarily intended to supplement existing data bases such as the JPL or NIST catalogs. Presently it contains entries for 111 species. Other sections of the database include information on the programs used for fitting spectra and creating the catalog entries, along with detailed information on some spectroscopy projects performed at the university of Cologne and a list of known inter-and circumstellar molecules. The database can be accessed online free of charge via http://www.ph1.uni-koeln.de/vorhersagen/ or alternatively via the shortcut http://www.cdms.de.

The Cologne Database for Molecular Spectroscopy, CDMS, was founded 1998 to provide in its catalog section line lists of mostly molecular species which are or may be observed in various astronomical sources by means of (usually) radio astronomical means. The line lists contain transition frequencies with qualified accuracies, intensities, quantum numbers, as well as further auxilary information. They have been generated from critically evaluated experimental line lists, mostly from laboratory experiments, employing established Hamiltonian models. Seperate entries exist for different isotopic species and usually also for different vibrational states. As of December 2015, the number of entries is 792. They are available online as ascii tables with additional files documenting information on the entries.The Virtual Atomic and Molecular Data Centre, VAMDC, was founded more than 5 years ago as a common platform for atomic and molecular data. This platform facilitates exchange not only between spectroscopic databases related to astrophysics or astrochemistry, but also with collisional and kinetic databases. A dedicated infrastructure was developed to provide a common data format in the various databases enabling queries to a large variety of databases on atomic and molecular data at once.For CDMS, the incorporation in VAMDC was combined with several modifications on the generation of CDMS catalog entries. Here we introduce related changes to the data structure and the data content in the CDMS. The new data scheme allows us to incorporate all previous data entries but in addition allows us also to include entries based on new theoretical descriptions. Moreover, the CDMS entries have been transferred into a mySQL database format. These developments within the VAMDC framework have in part been driven by the needs of the astronomical community to be able to deal efficiently with large data sets obtained with the Herschel Space Telescope or, more recently, with the Atacama Large Millimeter Array.

Context. The Cygnus X region is one of the richest star formation sites in the Galaxy. There is a long-standing discussion about whether the region is a chance superposition of several complexes along the line of sight or a single coherent complex at a distance of 1.5 to 2 kpc. Aims. Combining a 13 CO 2 → 1 survey taken with the KOSMA 3 m telescope with mid-IR images from MSX provides a way to improve our understanding of the spatial structure of the complex. The physical properties of the molecular gas can be derived in more detail as it was done in former studies. Methods. Cygnus X has been mapped in 13 CO J = 2 → 1 (10.8 deg 2 ) at an angular resolution of 130 , as well as for smaller areas in 12 CO and 13 CO J = 3 → 2 (90 ), using the KOSMA 3 m submm-telescope. Results. We identified 91 clumps in 13 CO 2 → 1 that have a typical excitation temperature of 10−30 K, an average density of 1.3 × 10 3 cm −3 , radii of 1−8 pc, and masses of a few hundred to several ten thousand M . The main cloud complexes, the northern part (M 2.8 × 10 5 M ) including DR21 and W75N and the southern region (M 4.5 × 10 5 M ) with IC 1318 b/c and AFGL2591, show differences in their physical properties. The 13 CO emission is closely associated with mid-IR emission seen with MSX. We find evidence that Cygnus OB2 and Cygnus OB9 are affecting the molecular material in Cygnus X. Conclusions. Since essentially all molecular cloud complexes in Cygnus X form groups that are connected by molecular emission (visible in channel and position-velocity maps) and partly show evidence of interaction with UV radiation, we conclude that most of the objects seen in this region are located at the same distance, i.e., that of the OB2 cluster at ∼1.7 kpc, which is also consistent with the distances of other OB associations (OB9, OB1) in Cygnus X.

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