SIMBAD references

This paper presents results of a program to derive distances of high-velocity clouds (HVCs) through measurement of absorption in the CaIIH and K lines. The problems of the method and their solutions are discussed in detail. A probable detection of absorption toward the Seyfert galaxy Mark106 is reported, which gives a Ca⁺ abundance of (17±6)x10^–9 in HVC complex A. The non-detection of CaII absorption against a stellar probe sets a tentative lower limit of 1.6kpc to the distance of complex A. Non-detections of HVC CaII lines in 9 stars projected on complexes M, C and H may give distance limits, if the Ca⁺/HI ratio in those HVCs can be derived from absorptions against extra-galactic probes. High-resolution HI observations are required to get reliable Ca⁺ abundances. Westerbork HI synthesis observations are reported for several directions together with profiles obtained at the Effelsberg 100-meter dish. From results on several HVCs, we conclude that the Ca⁺/HI ratio may vary strongly between different HVC complexes.