Astron. Astrophys. 350, 447-456 (1999)

3. The Effelsberg observations

Here, we are reducing data from the 100-m Effelsberg telescope, observed by both Reich et al. (1984) and Reich et al. (1990b). The equipment, observing and calibration procedures are described in some detail in both Reich et al. (1984) and Junkes et al. (1987a). Some of the telescope and observing parameters are listed in Table 1.

Table 1. Receiver data, telescope parameters and assumed calibrator values for the Effelsberg survey. The rms noise and brightness sensitivity information are given for the resolution images. The value is also quoted for angular resolution. The uncertainty in the polarisation position-angle is given as a function of the polarised intensity PI (mJy/b.a.).

The receiver used was a 3 channel, cooled FET (field effect transistor) based device. Coupled with the polarimeter (Reich et al. 1984), this arrangement produced data for the Stokes parameters I, Q and U.

The Effelsberg radio telescope itself is a large and fully steerable parabolic dish, 100 m in diameter, on an alt-azimuth mounting. The observations were made by scanning the telescope in directions of Galactic longitude (l-scans) and Galactic latitude (b-scans), at a rate of per minute in the coordinate system. A separation of was used between adjacent scans and adjacent pixels, as this provided fully sampled data (i.e. more than 2 points per HPBW). Each scan was typically in length. Because of this, the area to be observed was built up as a series of smaller regions, each of which was approximately in extent.

Calibration of the data was performed by scaling the observations against the bright, point-like source 3C286 (see Table 1). The flux density of this source is taken from Baars et al. (1977), and the polarimetric characteristics from Tabara & Inoue (1980).

© European Southern Observatory (ESO) 1999

Online publication: October 4, 1999
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