VIII/57 Fluxes of Faint Radio Sources at 2.7/4.75 GHz (Forkert+, 1987)
Fluxes of Faint Radio Sources at 2.7/4.75 GHz (32.8d--33.5°)
Forkert, T. and Altschuler, D. R.
<Astron. Astrophys. Suppl. Ser. 70, 77 (1987)>
=1987A&AS...70...77F 1987A&AS...70...77F
ADC_Keywords: Radio continuum ; Radio sources
Description:
This table is a compilation of revised 4.75 GHz and 2.695 GHz flux
densities and corresponding spectral indices at epoch 1986.2 of a
catalog of 239 sources, which has previously been published by Forkert
and Altschuler, (1987A&AS...70...77F 1987A&AS...70...77F). It comprises 209 sources
(marked 'A'), forming a complete, flux density limited sample above 50
mJy at 4.76 GHz in 1981.9 (Altschuler, 1986A&AS...65..267A 1986A&AS...65..267A), and 30
sources (marked 'a') below this limit, but with 5.0 GHz flux densities
from 1971.0 (Davis, 1971AJ.....76..980D 1971AJ.....76..980D). The catalogue covers a
narrow strip of the sky around declination of 33 degrees. The flux
densities were calibrated with 3C286 on the scale of Kellermann,
Pauliny-Toth and Williams (1969ApJ...157....1K 1969ApJ...157....1K).
After publication of the catalog a statistical analysis for flux
density variability in the data has been performed (Forkert, 1990),
using 6cm flux density measurements of Davis (1971AJ.....76..980D 1971AJ.....76..980D) and
Altschuler (1986A&AS...65..267A 1986A&AS...65..267A) and the 2.695 GHz flux densities of
Pauliny-Toth et al. (1974A&A....35..421P 1974A&A....35..421P), the details and results of
which are going to be published elsewhere (Altschuler & Forkert, in
preparation). For the purposes of this analysis it has become
necessary to obtain more individual error estimates of the 1986.2
data, not dominated by the effect of overall scale errors. This
revision for some of the sources also led to slightly different flux
densities from those previously published.
The variability study proved the flux density errors to represent the
individual 1-sigma uncertainties, WITHOUT the effect of overall scale
errors. From the aforementioned comparison with other measurements
scale errors of ∼1% at 2.695 GHz and ∼3% at 4.75 GHz seem likely.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
radfaint.dat 103 239 Fluxes of Faint Radio Sources at 2.7/4.75 GHz
(32.8° < Dec < 33.5°)
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Byte-by-byte Description of file: radfaint.dat
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Bytes Format Units Label Explanations
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2- 4 I3 --- Seqno Sequence number of source (1)
6- 14 A9 --- Name IAU name of source (1)
16- 17 I2 h RAh Right Ascension (B1950) (hour) (2)
19- 20 I2 min RAm Right Ascension (B1950) (min)
22- 25 F4.1 s RAs Right Ascension (B1950) (sec)
27 A1 --- DE- Declination sign (B1950) (2)
28- 29 I2 deg DEd Declination (B1950) (deg)
31- 32 I2 arcmin DEm Declination (B1950) (arcmin)
34- 35 I2 arcsec DEs Declination (B1950) (arcsec)
37- 43 F7.2 mJy S2695 ? Peak flux density of source at 2695 MHz
45- 49 F5.2 mJy e_S2695 ? Error on 2695 flux density
51- 57 F7.2 mJy S4750 ? Peak flux density of source at 4750 MHz
59- 63 F5.2 mJy e_S4750 ? Error on 4750 flux density
65- 70 F6.3 --- Sp+Index ? Spectral index between 2.7 and 4.75 GHz (3)
72- 76 F5.3 --- e_Sp+Index ? Error on spectral index (3)
78- 84 A7 --- Oname Other name of source
86-103 A18 --- comment Comments on source (4)
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Note (1): These columns give the sequence number and the name of the
source. The number is assigned sequentially in right ascension to all
sources in the catalog. The name is assigned using IAU conventions, as
hhmm+ddmm, with a letter appended at the end if necessary to determine
uniqueness.
Note (2): These columns contain the B1950 coordinates of the source, in
radians and in degrees. The sources were observed at the 5 GHz
positions determined by Altschuler (1986A&AS...65..267A 1986A&AS...65..267A). Positional
errors at 5 GHz are given in that paper.
Note (3): These columns give the spectral index and error. The spectral
index was computed as:
alpha = 1.77 * ln [S2.7/S4.75] ( Sν ∝ να )
and its error as:
e_alpha = 1.77 * sqrt [ (sigmatot/S4.75_)2 + (sigmatot/S2.7_)2 ]
where sigma_tot was estimated from measurements of individual scans
and is typically 3 mJy (see the paper for details).
Note (4): This column gives comments on the source as follows:
a, A - Source below or above the completeness limit of 50mJy in the
survey at 4.76GHz in 1981.9 of Altschuler, Altschuler
(1986A&AS...65..267A 1986A&AS...65..267A).
d, D - Source below or above the completeness limit of 67mJy in the
survey at 5.0GHz in 1971.0 of Davis, Davis (1971AJ.....76..980D 1971AJ.....76..980D)
c_x - Confusing components were present at x cm wavelength and have
been subtracted
e?_x - Possibly extended at x cm wavelength
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History:
The data were provided by T. Forkert to H. Andernach in late 1990,
who provided them to ADS/Einline (CfA, Harvard-Smithsonian Center
for Astrophysics, Cambrigde MA)
References:
Forkert, T. 1990, Ph.D.-thesis, Univ.Bonn/Max-Planck-Institut fuer
Radioastronomie, Bonn.
(End) Patricio Ortiz [CDS] 23-Apr-1999