CaII K interstellar observations towards early disc and halostars - Paper II; distances to IVCs and HVCs

Abstract

We compare existing high spectral resolution (R=40,000) CaII K observations towards 88 mainly B-type stars, and new observations at R=10,000 towards 3 stars, with 21-cm HI emission-line profiles, in order to search for optical absorption towards known intermediate and high velocity cloud complexes. Given certain assumptions, limits to the gas phase abundance of CaII are estimated for the cloud components. We use the data to derive the following distances from the Galactic plane (z); 1) Tentative lower z-height limits of 2800 pc and 4100 pc towards Complex C using lack of absorption in the spectra of HD 341617 and PG 0855+294. 2) A weak lower z-height of 1400 pc towards Complex WA-WB using lack of absorption in EC 09470-1433 and weak lower limit of 2470 pc with EC 09452-1403. 3) An upper z-height of 2470 pc towards a southern intermediate velocity cloud (IVC) with v_LSR=-55 km/s using PG 2351+198. 4) Detection of a possible IVC in CaK absorption at v_LSR=+52 km/s using EC 20104-2944. No associated HI in emission is detected. At this position, normal Galactic rotation predicts velocities of up to +25 km/s. The detection puts an upper z-height of 1860 pc to the cloud. 5) Tentative HI and CaK detections towards an IVC at +70 km/s in the direction of HVC Complex WE, sightline EC 06387-8045, indicating that the IVC may be at a z-height lower than 1770 pc. 6) Detection of CaK absorption in the spectrum of PG 0855+294 in the direction of IV20, indicating that this IVC has a z-height smaller than 4100 pc. 7) A weak lower z-height of 4300 pc towards a small HVC with v_LSR=+115 km/s at l,b=200,+52, using lack of absorption in the CaK spectrum of PG 0955+291.

13 pages, 5 figures. Accepted for publication in MNRAS, May 13 2004

References in corpus (9)

• High Velocity Clouds: Building Blocks of the Local Group
• Distances and Metallicities of High- and Intermediate-Velocity Clouds
• The Magellanic Stream, High-Velocity Clouds and the Sculptor Group
• Dependence of Gas Phase Abundances in the ISM on Column Density
• Abundances and Physical Conditions in the Warm Neutral Medium Towards mu Columbae
• HI spectra and column densities toward HVC and IVC probes
• WHAM Observations of H-alpha from High-Velocity Clouds: Are They Galactic or Extragalactic?
• A Map of the Ionized Component of the Intermediate Velocity Cloud Complex K
• Multiwavelength observations of the M15 intermediate velocity cloud

Cited by in corpus (6)

• Hot subluminous stars
• Imaging the transition between pre-planetary and planetary nebulae: Integral Field Spectroscopy of hot post-AGB stars with NIFS
• Hot horizontal branch stars in NGC 288 - effects of diffusion and stratification on their atmospheric parameters
• High-resolution spectroscopy of the high velocity hot post-AGB star IRAS 18379-1707 (LS 5112)
• Observations towards early-type stars in the ESO-POP survey: II -- searches for intermediate and high velocity clouds
• A Catalogue of Field Horizontal Branch Stars Aligned with High Velocity Clouds