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Survey of the Galactic plane at 4.785 GHz
W.J. Altenhoff, D. Downes, T.Pauls and J. Schraml
A survey of the galactic plane has been made with the Effelsberg 100-m
telescope at a frequency of 4.875 GHz with a beamwidth of 2.6'. The data
are presented as radio contour maps covering l=357.5 to 60^o, b=+-1^o,
together a list of 1186 radio sources.
The primary calibration source was NGC7027, which was assumed to have a flux
density of 5.9 Jy. The uncertainty in the day-to-day thermal calibration
was +-5 to 10%. For a point source, 1 Jy = 1.3+-0.03 K antenna
temperature = 2.00 +- 0.05 K main-beam brightness temperature. For contours
which extend over several degrees of sky, we estimate that 1 K Ta = 1.1K Tb.
Table 1 is a list of 1186 sources from the survey. Some sources in relatively
unconfused fields were reobserved with short scans in l and b ,
and fitted with gaussians.
The sources parameters in table 1 were derived as follows:
* in Remarks column: positions, half-power widths and intensities
from gaussian fits;
** in Remarks column: complex source; position from contour map;
positions, half-power width and intensity from gaussian fits;
all other sources: parameters from contour maps.
Diameters measured from contour maps are notoriously unreliable and we
expect that synthesis observations with beamwidths of a few arcsec would
resolve many of the sources into compact components. We therefore did not
de-convolve the apparent diameters, or estimate integrated fluxes for the
- 1,2 Source coordinates in galactic longitude and latitude, accurate
- 3,4 Source coordinates RA and DEC 1950.
- 5 Peak flux (Jy) of the source after the background has been subtracted.
The units are in Jy for equivalent point sources. For the flux
derived from gaussian fits, the uncertainty is ~5 %.
- 6 Asterisks denote gaussian fits. Designation are given only for
well-known sources with widely-used names, particularly from
molecular-line studies. In a complex of sources, we give the name
only for the strongest peak. With increasingly higher resolution,
most of the older source designations have become obsolete, and we
suggest that the sources should be mainly referred to by l/b.
- 7 Approximate source diameter, as observed with 2.6' beam.
The value is the geometric mean of the half-power widths in l-b.
For sources with a peak intensity of 0.1 Jy, the letter P stands
for point source, and "EXT" means that the source is extended,
and the exact size is uncertain to ~10%. The diameters of the
remaining sources were estimated to the nearest 0.5' from the
contour map, and should be regarded with caution.
- 8 Integrated fluxes were estimated (****only in CATS!****) as
Flux = Peak flux * (diam/2.6')^2.
Glll.lll+b.bbb - Bonn (Effelsberg) at 4875 MHz
l b RA1950 DEC1950 P_flux diam'Rem T_flux
G357.658-0.079 17 37 00.9 -30 56 37 5.18 4.0 ** 12.26