The WSRT 327 MHz Galactic Plane Survey

The Westerbork Synthesis Radio Telescope (WSRT) in the Netherlands has been used to survey a section of the galactic plane at a radio frequency of 327MHz. Twenty-three overlapping synthesis fields were observed, covering galactic co-ordinates |b|<1.6d, 43d < l < 91d. Each field was observed at two epochs, several years apart, to identify variable sources. Intensity data from the seperate epochs were combined, and the resulting images mosaiced to produce a single image of the entire survey region. Sensitivity of the mosaic is typically a few mJy. Resolution is 1' by 1'csc(dec).

The survey image provides our first high resolution view of the Galaxy at low radio frequencies, and includes sections of the Sagittarius and Cygnus arms. These sections contain numerous extended features, among them supernova remnants, HII regions, "bubbles" of thermal emission, and large patches of amorphous galactic thermal emission. The inter-arm region is characterized by lower densities of extended features, but numerous discrete compact radio sources, most of which are background objects such as quasars and other types of active galactic nuclei. However, the resolution, sensitivity and low frequency of this survey make it ideal for detecting weak, non-thermal compact galactic sources, e.g. compact, low surface brightness SNRs and radio stars.

The image at the top of this page shows the region around the HC40 supernova remnant. Images of the entire survey region can be viewed or downloaded by clicking on the thumbnail images below. Each of the sub-image covers roughly 7 degrees in longitude.

Image of Galactic Longitude range 77 to 84 degrees.
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Image of Galactic Longitude range 70 to 77 degrees.
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Image of Galactic Longitude range 63 to 70 degrees.
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Image of Galactic Longitude range 57 to 64 degrees.
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Image of Galactic Longitude range 50 to 57 degrees.
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Image of Galactic Longitude range 43 to 50 degrees.
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Taylor, A.R., Goss. W.M., Coleman, P.H., van Leeuwen, J. & Wallace, B.J. 1996, Astrophysical Journal Supplementary Series, 107, 239.

Last Modified: 10 December 1996