A&A Supplement series, Vol. 123, May II 1997, 43-58
Received May 23; accepted August 28, 1996
U.J. Schwarz - W.M. Goss - P.M.W. Kalberla
Send offprint request: U.J. Schwarz
Kapteyn Astronomical Institute, Groningen University, Postbus 800, 9700 AV Groningen, The Netherlands
National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801, U.S.A.
Radioastronomisches Institut, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn 1, Germany
We present high resolution images of the entire galactic HI spectrum of Cas A and display the whole data cube in various ways; the spatial resolution is 30 arcsec and the velocity resolution is 0.62 km s. In previous studies, observations are described either with lower velocity resolution or with a limited velocity range (below -30 km s), (Bieging et al. 1991; Reynoso et al. 1997). Here we concentrate the discussion on the local HI gas, with velocities between -10 and +10 km s. At a velocity of -1.5 km s we find a cold HI feature with a kinetic temperature of typically 25 K, with a small region of 1 by 2 arcmin with a kinetic temperature below 10 K. This feature can be associated with a CO feature observed by Wilson et al. (1993). Based on the new HI absorption results we derive the ratio .
keywords: ISM: Cas; clouds atoms -- radio lines: ISM