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The 5 GHz strong source surveys. IV. Survey or the area between declination 35 and 70 degrees and summary of source counts, spectra and optical identifications

Pauliny-Toth I.I.K., Witzel A., Preuss E., Kuehr H., Kellermann K.I. and Formalont E.B.


A new zone (S4) has been surveyed at 5 GHz and is essentially complete above 0.5 Jy. A total of 269 sources above this flux density were found in an area of 1.71 sr between declinations of 35^o and 70^o. Accurate flux densities at 2.7, 5.0, and 10.7 GHz are given, together with source coordinates accurate to between 1 and 5 arcsec, and proposed optical identifications. Sources below the completeness limit are also listed, giving a catalog of 484 sources. The results of the S4 survey are combined with those of the previous 5 GHz surveys, with a 5 GHz strong source sample derived from the Parkes 2.7 GHz surveys, and with samples taken from deeper surveys made at 5 GHz to discuss the source counts, the source spectra and their relation to the optical identifications. The 5 GHz source counts differ from those derived at lower frequencies in that there is less evidence for either a steepening of the counts at high flux densities or for their convergence at very low flux densities. The counts indicate a possible anisotropy related to the supergalactic system.

The survey instrument was the 92-m telescope, equipped with a cooled parametric amplifier centered at 5000 MHz. Beam switching was used, with a 7.2 arcmin separation of the two beams, each of which had a HPBW of 2.7 arcmin. Observations were made in March and April 1972. Two small gaps (both at |b|<10d) were excluded.
Those sources in the finding list lying more than 10 deg. from the galactic plane were observed with the 100-m telescope at frequencies of 2.7, 10.7, and 4.9 GHz. Most of those observations were made in August and December 1972 and December 1974.
For the calibration of the flux-density scales, data for three of the standard sources, 3C 123, 3C 147, and 3C 295 were taken from Kellermann et al. (1969; hereafter KPW) for the 2.7- and 4.9-GHz observations. For the latter frequency, the 5.0 GHz flux densities given in KPW were adjusted to 4.9 GHz, using the spectral index computed from the KPW 2.7- and 5.0-GHz flux densities. At 10.7 GHz, the calibration data were taken from Kellermann and Pauliny-Toth (1973). Once the spectral indices of the sources in the survey list had been determined, they were used to correct the measured 4.9-GHz flux densities to 5.0 GHz, for consistency with the previous S surveys.

The typical error for a source having S=0.5 Jy is thus about 2.5, 1.5 and 8 % at 2.7, 5.0 and 10.7 GHz, respectively.

The absolute scale of flux densities is that of KPW at 2.7 and 5.0 GHz and that of Kellermann and Pauliny-Toth (1973) at 10.7 GHz. These scales agree to within 3 % with new, absolute scale of flux densities derived by Baars et al. (1977).

The above text was prepared by the CATS team, and the source table
was reconstructed  from Dixon's Master List with several dozen
typos corrected H.Andernach 3/96

S4-name      RADEC_B1950        S_5GHz  S11cm S2.8cm
S4 0003+38  000322.34+380333.2  0.504   0.61   0.60