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M. Scherer
- M. Havenith
-
R. Mauersberger
- T.L. Wilson
Institut für Angewandte Physik der Universität Bonn,
Wegelerstr. 8, D-53115 Bonn, Germany
Steward Observatory, The University of Arizona,
Tucson, AZ85721, U.S.A.
Max-Planck-Institut
für Radioastronomie, Auf dem Hügel 69,
D-53121 Bonn, Germany
Submillimeter Telescope Observatory, The University of Arizona,
Tucson, AZ85721, U.S.A.
Abstract: The MPIfR 100m telescope, the NRAO 12m
telescope,
and the IRAM 30m telescope were used to search for low lying
rotational transitions of the water dimer, (H
O)
,
toward the Galactic cloud cores Orion-KL, W51d, W51e1e2,
NGC7538, SgrB2(M) and L134N, and toward comet Hale-Bopp. The comet
was
observed on December 20, 1996 and March 25/26, 1997 (i.e.
near perihelion on April 1) at 24GHz. No lines of
(H
O)
were found. Our limit for the abundance
of (H
O)
relative to that of water (from
H
O data) is typically
toward dense cloud cores. Toward Orion-KL an even more
stringent limit of <810
is derived.
The abundance of (H
O)
relative to H
is
typically
. Our data show that at perihelion
the production
rate of the water dimer of comet C/1995 O1 (Hale-Bopp) was
. This is less than 6% the production
rate of H
O.
Submitted to Astronomy & Astrophysics
e-mail contact: mauers@as.arizona.edu
guelin@iram.fr