VIII/17 The North 20cm Survey (White+ 1992)
The 1.4-GHz Northern Sky Catalog
White R.L., Becker R.H.
<Astrophys. J. Suppl. Ser. 79, 331 (1992)>
=1992ApJS...79..331W 1992ApJS...79..331W
ADC_Keywords: Radio sources
Description:
This catalog contains a list of 30239 radio sources at 1.4GHz over the
declination range of -5 to +82 degrees. This catalog is based on the
Green Bank 1.4GHz Northern Sky Survey (Condon and Broderick, 1986,
Cat. VIII/6) which was generated using the Green Bank 300 foot (91m)
telescope. The threshold for identifying a 1.4GHz radio source was set
at 100mJy. The catalog data include the source name, a confusion flag,
right ascension (1950), declination (1950), 1.4GHz flux, a flag to
indicate if the source is extended at 20cm, 4.85GHz flux (from Becker
et al., 1991, Cat. VIII/13), a flag to indicate if the source is
extended at 6cm, 365MHz flux (from the Texas Survey, Douglas et al.
1980; see Cat. VIII/42)), spectral index between 6 and 20 cm, and
spectral index between 20 and 80 cm. Where possible, the source name
is derived from the 6cm catalog of Becker et al. 1991 (Cat. VIII/13).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
north20.dat 69 31524 The 20cm catalog
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Byte-by-byte Description of file: north20.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- WB *20cm Name
12 A1 --- cFlg *[?] Confusion flag
14- 15 I2 h RAh Hours of right ascension (1950)
17- 18 I2 min RAm Minutes of RA
20- 23 F4.1 s RAs Seconds of RA
25 A1 --- DE- Sign of declination
26- 27 I2 deg DEd Degrees of declination (1950)
29- 30 I2 arcmin DEm Minutes of declination
32- 33 I2 arcsec DEs Seconds of declination
35- 41 I7 mJy S1.4 1.4GHz (20cm) flux
42 A1 --- n_S1.4 [*] if source is extended at 20cm, else blank
44- 50 I7 mJy S4.85 ? 4.85 GHz flux from Becker et al (Cat. VIII/13)
51 A1 --- n_S4.85 [*] if source is extended at 6cm, else blank
53- 59 I7 mJy S.365 ? 365MHz (80cm) flux from Texas survey, Douglas
et al. (see Cat. VIII/42)
61- 64 F4.1 --- Sp+Index *? Spectral index between 6 and 20cm
66- 69 F4.1 --- Sp+Index2 *? Spectral index between 20 and 80cm
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Note on WB:
20cm Name, constructed from RA, Dec HHMM+DDMM with A or B added at end
if needed to make name unique. When a 20cm source matches a sources in
the 6cm catalog of Becker, White & Edwards (1991, Cat. VIII/13) the
6cm name and position (good to 40" at the 90% confidence level) are
used. Sources without a 6cm counterpart have names ending in L; their
positions are only accurate to 160" at the 90% confidence level).
Note on cFlg:
? indicates that a 20cm source matched more than one 6cm or 80cm
source, so confusion is likely. In that case the additional matches
are listed in following lines.
Note on Sp+Index, Sp+Index2:
The values are blank if the source was not detected at 6cm/80cm.
The spectral index (alpha) is defined such that
S(nu) ∝ (nu)α
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References:
Becker, R.H., White, R.L. and Edwards, A.L. 1991, ApJS, 75, 1
(Cat. VIII/13)
Condon, J.J., and Broderick, J.J. 1986, AJ, 91, 1051
(Cat. VIII/6)
Douglas, J.N., Bash, F.N., Torrence, G.W., and Wolfe, C. 1980,
Univ. Tex., Publ. Astron., No. 17 (see Cat. VIII/42)
Condon. J.J., and Broderick, J.J. 1985, AJ, 90, 2540 (Cat. VIII/6)
(End) C.-H. Joseph Lyu [Hughes STX/NASA] 01-Aug-1995