J/AJ/87/859 Polarisation of 404 radio sources at 6 and 20cm (Perley, 1982)
The positions, structures and polarizations of 404 compact radio sources.
Perley R.A.
<Astron. J. 87, 859 (1982)>
=1982AJ.....87..859P 1982AJ.....87..859P
ADC_Keywords: Radio sources ; Polarization
Abstract:
Accurate positions of 404 compact radio sources used as calibrators by
the VLA are presented. In addition, the structure and polarization of
each source at both 4885 and 1465MHz are given. Eighty-five percent of
the sources have spectral indices flatter than 0.5; all of these are
dominated by an unresolved core. Half of these flat-spectrum sources
contain nearby, associated diffuse structure at a level exceeding
approximately 0.4% of the core brightness at 20cm.
Description:
The data were taken in two 24-hr sessions. The first, at 6cm, was on
18-19 November 1980, with 23 operational antennas. The latter, at
20cm, was on 18-19 February 1981, with 26 operational antennas.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 134 404 Positions, Structures and Polarization of
404 Compact Radio Sources
notes.dat 80 252 Individual notes (table3 of paper)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name IAU name, based on 1950 position
10- 17 A8 --- AName Alternative name (3C, 4C) (1)
19- 20 I2 h RAh Right ascension (1950.0)
22- 23 I2 min RAm Right ascension (1950.0)
25- 30 F6.3 s RAs Right ascension (1950.0)
32 A1 --- DE- Declination sign (1950.0)
33- 34 I2 deg DEd Declination (1950.0)
36- 37 I2 arcmin DEm Declination (1950.0)
39- 43 F5.2 arcsec DEs Declination (1950.0)
45- 49 F5.2 Jy S6cm Flux density at 6cm (4885MHz) (2)
50 A1 --- u_S6cm Uncertainty flag on S6cm
52- 56 F5.2 Jy S20cm Flux density at 20cm (1464MHz) (2)
57 A1 --- u_S20cm Uncertainty flag on S20cm
59- 63 F5.2 --- Sp-Index Spectral index alpha206
64 A1 --- u_Sp-Index Uncertainty flag on Sp+Index
66- 68 I3 mJy pS6cm ? Polarized flux at 6cm (4885MHz) (3)
69 A1 --- u_pS6cm Uncertainty flag on pS6cm
71- 73 I3 deg PA6cm ? Position angle of polarized flux at 6cm (3)
74 A1 --- u_PA6cm Uncertainty flag on PA6cm
75- 78 F4.1 % dp6cm ? Degree of polarized flux at 6cm (4885MHz)
79 A1 --- u_dp6cm Uncertainty flag on dp6cm
81- 84 I4 mJy pS20cm ? Polarized flux at 20cm (3)
86- 88 I3 deg PA20cm ? Position angle of polarized flux at 20cm (3)
90- 94 F5.2 % dp20cm ? Degree of polarized flux at 20cm (1465MHz)
95 A1 --- l_B6cmu Limit flag on B6cmu
96- 98 F3.1 % B6cmu ? Upper limit (as % of peak) of the peak
brightness of secondary structure, at 6cm
99 A1 --- n_B6cmu [*] *: source slightly resolved
100-103 F4.1 --- B6cm ? Peak brightness of secondary structure,
at 6cm (4)
104 A1 --- n_B6cm [*] *: source slightly resolved
105 A1 --- l_B20cmu Limit flag on B20cmu
106-109 F4.1 % B20cmu ? Upper limit (as % of peak) of peak
brightness of secondary structure,
at 20cm (4)
110 A1 --- n_B20cmu [*] *: source slightly resolved
112-116 F5.1 --- B20cm ? Peak brightness of secondary structure, at
20cm (4)
117 A1 --- n_B20cm [*] *: source slightly resolved
118-119 A2 --- OID [QG BL EF?] Optical identification (5)
121-125 F5.2 mag Vmag ? Visual magnitude of optical identification
127-131 F5.3 --- z ? Redshift
133 A1 --- n_OID [+] +: optical ID from Hewitt and Burbidge,
1980ApJS...43...57H 1980ApJS...43...57H
134 A1 --- Note [*] *: Note detailed in notes.dat file
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Note (1): It is often difficult to decide whether a given 4C source is
to be identified with a compact source. A conservative approach has
been used.
Note (2): This is the flux of the core in all cases where this can be
determined. Sources where this could not be done have an asterisk in
column 14 (n_B6) or 15 (n_B20). The error in the flux is estimated to
be less than ∼sqrt[(0.03S)2+(0.002)2]Jy, with S in Jy.
Note (3): The listed flux applies to the core only, unless the core
cannot be distinguished, in which case the listing applies to the
whole source. The error in polarized flux is estimated to be
sqrt[4+(0.4S)2]mJy, where S is the total flux in Jy. The error in
position angle is strongly dependent upon the polarized flux, and is
roughly given by 65 sqrt[4+(0.4S)2]/m degrees.
Note (4): Listed secondaries are generally found within the clean-search
window defined earlier. Occasionally, larger windows were searched to
find more distant structure. The absence of a listed secondary does
not guarantee the source has none -it may lie outside the search
window. This is particularly true at 6cm where the search window was
6.4arcsec wide. Entries marked by an asterisk indicate the source is
slightly resolved, but not enough for a reliable map.
Note (5): Optical identification:
BL: BL Lac
EF: Empty field
G: Galaxy
Q: QSO
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Name
10- 80 A71 --- Note Text of the note
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History:
From the CATS data-base (ftp://cats.sao.ru/VLA404/;
R191 in Andernach's list)
(End) Patricia Bauer [CDS] 19-Nov-2003