The WSRT 327 MHz Galactic Plane Survey

[WSRT survey mosaic image]

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 a low-resolution overview of the entire survey. Subimages of the survey are available below, each covering roughly 7 degrees of Galactic longitude.

Image of Galactic Longitude range 91 to 84 degrees.


Image of Galactic Longitude range 84 to 77 degrees.


Image of Galactic Longitude range 77 to 70 degrees.


Image of Galactic Longitude range 70 to 63 degrees.


Image of Galactic Longitude range 64 to 57 degrees.


Image of Galactic Longitude range 57 to 50 degrees.


Image of Galactic Longitude range 50 to 43 degrees.


The WSRT 327 MHz Galactic Plane Discrete Source Catalogue

Two-dimensional Gaussian models have been fit to all compact sources in the images. The source catalogue lists positions, flux densities and angular sizes for 3,984 sources. It is available as a UNIX compressed postscript file [164 Kbytes] and an ASCII text file [339 Kbytes]. The postscript version of the catalogue produces a table that is 73 pages long.

For more detailed information on the survey project and statistical analysis of the compact source population, please refer to:

Taylor, A.R., Goss. W.M., Coleman, P.H., van Leeuwen, J. & Wallace, B.J. 1996, Astrophysical Journal Supplementary Series, 107, 239.

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Comments and inquiries to Russ Taylor (
Last Modified: 1999 July 11

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