We have collected radio data of Galactic HII regions from 24 published works and built a self-consistent database of 1442 sources. This work has resulted in the construction of what we have called Master Catalog which consists in 11 different sub-catalogs storing the original information from the source references. In particular, the sub-catalogs list flux densities and diameters as well as radio line velocities, line widths and line temperatures; errors are given on these quantities.
From this large data set observed at a range of frequencies and beamwidths, we have produced a readibily accessible Synthetic Catalog giving the flux density, diameter and velocity (where available) at 2.7 GHz, the frequency where most data are given. Errors on these observed parameters are derived using the procedures discussed in Sect. 3.
It should be emphasized that the Catalog is a compilation of published radio data on HII regions; it is not a complete survey down to the faintest flux density level listed. We argue in Sect. 4 that it is probably complete to a flux density of 1 Jy. Nevertheless, the Catalog provides an up to date finding list for the brightest HII regions available for further study at microwave and submillimeter wavelenghts. The Synthetic Catalog is also particularly relevant to future high sensitivity CMB mapping projects such as PLANCK. We have shown in Sect. 5 that the HII region Galactic distribution can contribute to the straylight radiation, while individual compact bright HII regions have a role as calibrators and as pointing and beamshape indicators.
The Master Catalog and the Synthetic Catalog are only available via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/397/213 Color figures can be obtained via e-mail request to paladini@sissa.it.
Acknowledgements
We wish to thank C. Witebsky for providing us with the COBE-HII compilation and T. A. Kuchar and F. O. Clark for making their radio and IRAS data available prior to publication. The authors made use of the database CATS (Verkhodanov et al. 1997) of the Special Astrophysical Observatory. We are also grateful to G. De Zotti and H. J. Wendker for useful discussions and suggestions. We thank L. Cambrecy for valuable comments to our work. R. Paladini acknowledges financial support from a NATO International Exchange Scientific Programme grant and from a Marie Curie Training Site fellowship. We gratefully acknowledge K. M. Górski and all the people involved in the realization of the tools of HEALPix pixelisation.
Copyright ESO 2003