We present firm evidence that one of the major high velocity clouds
(HVCs), Complex A, lies in the Milky Way Halo, at a vertical distance z
= 3 - 7 kpc from the Galactic plane. For clouds MII/MIII, Danly et al.
and Keenan et al. had already found z <5 kpc. We further report that
the metallicity in the largest HVC, Complex C, is at least 0.1 solar.
CaII/HI ratios in 6 HVCs, ranging from 0.002 to 0.07 times solar, set
lower limits to their metallicities. Blitz et al. have recently
suggested that most of the HVCs are relatively unprocessed,
extragalactic remnants of the gas which formed the Local Group of
galaxies. However, the results mentioned above indicate that several
major HVC complexes are neither primordial nor extragalactic. For the
smaller HVCs, some of which have much higher velocities, a location in
the Local Group remains a possibility.
|Title of host publication||The local bubble and beyond|
|Subtitle of host publication||Lyman-Spitzer-Colloquium; proceedings of the IAU Colloquium no. 166 held in Garching, Germany, 21-25 April 1997|
|Place of Publication||Berlin|
|Publication status||Published - 1998|
|Name||Lecture notes in physics|