The MOST has been used for a new 843-MHz survey of the galactic plane in the
longitude range 335
- 5, and galactic latitudes within +/-
2.5. The resolution is 90 arcsec x 43.5 arcsec, and flux density lower
limit 5 mJy beam. Primarily on the basis of a separation between
thermal and non-thermal emission, seventeen objects have been identified as new
potential SNRs. A second-epoch survey is planned to investigate
radio variability of sources. MOST observations of a six square degree at
l = 312, b = 0 show an abundance of low-surface-brightness
extended structure. This may be linked to the extended HII envelopes that have
been postulated to explain certain galactic phenomena, or may represent an
intermediate state between classical HII regions and the warm ionized medium.
The 64-m Parkes telescope has been used for a 2.4-GHz polarimetric continuum
survey of the southern galactic plane at longitudes between 238 and
5 and latitudes within +/-9; the lower intensity limits for
continuum and polarized emission are 12 and 4 mJy beam. The images
reveal a large amount of structure and detail, including a considerable number
of low-surface loops and spurs.
A consortium of 33 scientists from Canada and other countries is using the DRAO
Synthesis Telescope for a galactic plane survey, consisting of imaging of the
continuum and HI emission in a strip 9.3 degrees wide along the plane between
longitudes 75 and 145. The observations will be complemented by
observations at other wavelengths, provided by international partners in the
project, in particular CO images from FCRAO, high-resolution IR data from
further computer processing of IRAS data (IPAC-JPL), 151-MHz continuum data
from the University of Cambridge, and 232- and 327-MHz data from the Beijing
Astronomical Observatory. The DRAO survey observations began in 1995 and will
occupy most of the time of the Telescope until the year 2000. The data will be
made public beginning in 1988 through the Canadian Astronomical Data Centre in
Victoria. One of the first results is the discovery of a galactic ‘chimney’,
associated with the HII region W4 (IC 1805) in the Perseus Arm. The combined
winds of a cluster of nine O-type stars have blown out through the galactic
disk, an example of a conduit for replenishment of the galactic halo from the
disk.