Canadian Galactic Plane Survey

The Canadian Galactic Plane Survey (CGPS) is a project aimed at improving our understanding of the constituents and processes of the interstellar medium (ISM) in our Galaxy. To this end, wide-field images of unprecedented detail are being assembled at many wavelengths by a consortium of astronomers from Canadian and international institutions. These will allow us to study dust grains, molecular gas, atomic gas, ionized gas, and relativistic plasmas, with spatial resolutions that are up to a factor of 10 better than in previous surveys, made possible by advances in technlogy and computing in recent years.

NRC-HIA's Dominion Radio Astrophysical Observatory (DRAO) is contributing data on the distribution and kinematics of atomic gas, as well as the distribution of ionized gas and relativistic plasmas. These observations are the centerpiece of the CGPS, and will cover Galactic longitudes from l=74.2 to 147.3 degrees and latitudes from b=-3.5 to +5.5 degrees, resolving features as small as 1 arcminute. The DRAO data products consist of a "data-cube" of the spatial distribution of atomic hydrogen over 256 velocity channels, with a spatial resolution of 1 arcminute and a velocity resolution of 1.2 km/s, together with 1420MHz continuum images of Stokes I, Q, U and V (i.e., full polarimetry) having 1 arcminute resolution, and 408 MHz continuum images of Stokes I at 3.5 arcminute resolution.

About 85% of the time available for observing at DRAO is being devoted to this project (the remainder is assigned to external proposals selected through a peer review process; proposal forms are available electronically). A total of 190 CGPS fields are being observed with the Synthesis Telescope during the 5-year observing phase, which ends in March 2000, with the data being reduced on-site from raw form to final images by a team of 6 people. Some data processing is also being carried out at the University of Calgary, notably the registration of source positions and flux densities relative to established scales, and reduction of the 1420MHz Stokes Q, U, and V data.

Other data products being contributed to the CGPS by consortium members include:

• high-resolution images of infra-red emission from the dust component, produced at far-infrared wavelengths by the California Institute of Technology, and in the mid-infrared by the Canadian Institute for Theoretical Astrophysics at the University of Toronto, both reprocessing data from the Infra-Red Astronomical Satellite (IRAS);
• information on the distribution and kinematics of the molecular gas, as traced by the carbon monoxide (CO) molecule, from data observed at the Five Colleges Radio Astronomy Observatory;
• data on the ionized gas and relativistic plasma components that will complement the DRAO data are being provided at 151MHz by the Mullard Radio Astronomy Observatory of the University of Cambridge, and at 232 and 327MHz by the Beijing Astronomical Observatory.

These are summarized in the table below:

Further information on the survey

CGPS page at the University of Calgary.