2007MNRAS.378..947S

We present CaII K and TIII optical spectra of early-type stars taken mainly from the ultraviolet and visual echelle spectrograph (UVES) Paranal Observatory Project, plus Hi 21-cm spectra, from the Vila-Elisa and Leiden-Dwingeloo Surveys, which are employed to obtain distances to intermediate- and high-velocity clouds (IHVCs). Hi emission at a velocity of -117 km/s towards the sightline HD30677 with column density ∼1.7x10¹⁹/cm2 has no corresponding CaII K absorption in the UVES spectrum, which has a signal-to-noise ratio (S/N) of 610 per resolution element. The star has a spectroscopically determined distance of 2.7 kpc, and hence sets this as a firm lower distance limit towards Anti-Centre cloud ACII. Towards another sightline (HD46185 with), HI at a velocity of +122 km/s and column density of 1.2x10¹⁹/cm2 is seen. The corresponding CaII K spectrum has a S/N of 780, although no absorption is observed at the cloud velocity. This similarly places a firm lower distance limit of 2.9 kpc towards this parcel of gas that may be an intermediate-velocity (IV) cloud. The lack of IV CaII absorption towards HD196426 at a S/N of 500 reinforces a lower distance limit of ∼700 pc towards this part of complex gp, where the Hi column density is 1.1x10¹⁹/cm2 and velocity is +78 km/s. Additionally, no IV CaII is seen in absorption in the spectrum of HD19445, which is strong in Hi with a column density of 8x10¹⁹/cm2 at a velocity of ∼ -42 km/s, placing a firm although uninteresting lower distance limit of 39 pc to this part of IV South. Finally, no high-velocity CaII K absorption is seen towards HD115363 at a S/N of 410, placing a lower distance of ∼3.2 kpc towards the HVC gas at velocity of ∼ +224 km/s and HI column density of 5.2x10¹⁹/cm2. This gas is in the same region of the sky as complex WE (Wakker 2001), but at higher velocities. The non-detection of CaII K absorption sets a lower distance of ∼3.2 kpc towards the HVC, which is unsurprising if this feature is indeed related to the Magellanic System.