Issue |
Astron. Astrophys. Suppl. Ser.
Volume 123, Number 1, May II 1997
|
|
---|---|---|
Page(s) | 43 - 58 | |
DOI | https://doi.org/10.1051/aas:1997305 | |
Published online | 15 May 1997 |
WSRT HI synthesis absorption study towards Cassiopeia A
1
Kapteyn Astronomical Institute, Groningen University, Postbus 800, 9700 AV Groningen, The Netherlands
2
National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801, U.S.A.
3
Radioastronomisches Institut, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn 1, Germany
Send offprint request to: U.J. Schwarz
Received:
23
May
1996
Accepted:
28
August
1996
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-1.
In previous studies, observations are described either with lower velocity
resolution or with a limited velocity range (below -30 km s-1),
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-1. At a velocity of -1.5
km s-1 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 13CO feature observed by
Wilson et al. (1993). Based on the new HI absorption results we derive the
ratio .
Key words: ISM: Cas; clouds atoms / radio lines: ISM
© European Southern Observatory (ESO), 1997