The Submillimeter Wave Astronomy Satellite - Mission Science Objectives
G. J. Melnick, A. Dalgarno,
N. R. Erickson, G. G Fazio, P. F. Goldsmith,
M. Harwit, D. J. Hollenbach, D. G. Koch,
D. A. Neufeld, R. Schieder,
R. L. Snell, J. R. Stauffer,
P. Thaddeus, V. Tolls, G. F. Winnewisser
Proceedings of "The Physics and Chemistry of Interstellar Molecular Clouds", held in Zermatt, Switzerland, 21-24 September 1993, G. Winnewisser and G. C. Pelz (Eds.), Springer 1995
Abstract:
The Submillimeter Wave Astronomy Satellite (SWAS) mission is dedicated to
the study of star formation and interstellar chemistry. To carry out
this mission, SWAS will survey dense
n(H2) > 103 cm-3 molecular clouds
within our galaxy in either the ground-state or a low-lying transition
of five astrophysically important species: H2O, H218O, O2, CI, and 13CO.
By observing these lines SWAS will: (1) test long-standing theories that
predict that these species are the dominant coolants of molecular clouds
during the early stages of their collapse to form stars and planets
and (2) supply heretofore missing information about the abundance
of key species central to the chemical models of dense interstellar gas.
SWAS will employ two independent Schottky barrier
diode mixers, passively cooled to about 150K, coupled to a
54 x 68 cm off-axis Cassegrain antenna with an aggregate surface
error of 11 µm rms.
During its three-year mission, SWAS will observe
giant and dark cloud cores with the goal of detecting
or setting an upper limit on the water abundance of 3*10-6
(relative to H2) and on the molecular oxygen abundance of
2*10-6 (relative to H2).
In addition, advantage will be taken of SWAS's relatively
large beam size of 3.2 x 4.0 arc minutes at 551 GHz and 3.6 x 4.5
arc minutes at 492 GHz to obtain large-area ( 1° x 1° )
maps of giant and dark clouds in the 13CO and CI lines.
With the use of a 1.4 GHz bandwidth acousto-optical spectrometer,
SWAS will have the ability to simultaneously observe the
H2O, O2, CI, and 13CO lines.
All measurements will be conducted with a velocity resolution
of less than 1 km/s.