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VIII/42 Texas Survey of radio sources at 365MHz (Douglas+ 1996)
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The Texas survey of radio sources covering -35.5{deg} < {delta} < 71.5{deg}
at 365MHz
Douglas J.N., Bash F.N., Bozyan F.A., Torrence G.W., Wolfe C.
<Astron. J. 111, 1945 (1996)>
=1996AJ....111.1945D
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ADC_Keywords: Radio sources
Abstract:
We present the Texas Survey of discrete radio sources between -35.5deg
and 71.5deg declination (B1950), which was carried out at 365MHz with
the Texas Interferometer during 1974-1983. The Survey lists accurate
positions with internal errors of about an arcsecond, flux densities
which for strong point sources have internal errors of about 1% and
total errors of about 5%, simple structure models and indications of
spectrum and variability for 66841 sources. Results of comparisons
with other data are presented, and show that the Survey is 90%
complete at 0.4Jy and 80% complete at 0.25Jy, is nearly free from
spurious sources, and has a lobeshift incidence which is reasonably
described by quality flags associated with each source.
Introduction:
The University of Texas Radio Astronomy Observatory (UTRAO) has
carried out, with the Texas Interferometer, a 365MHz survey of the sky
from -35.5 to +71.5{deg} declination, which was intended to be
complete to a flux density level of 0.25Jy, to provide positions with
an accuracy of about 1arcsec in both coordinates, to give accurate
flux densities and indication of source variability, and to give rough
structure models for each source.
The observations began in 1974 and were completed in 1983. A
preliminary version of one declination strip was published
(Douglas et al., 1980), and a number of intermediate versions of the
survey have been privately circulated for various purposes pending
completion of the final analysis and adjustment of the data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
txs.dat 133 66841 The Texas Survey
simpler.dat 133 15758 The sources in the simpler model.
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Byte-by-byte Description of file: txs.dat
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Bytes Format Units Label Explanations
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1 A1 --- Strip *[A-J] Main strip
2 A1 --- Aflg [*] * means simpler model(s) exist
3- 11 A9 --- TXS *Source name
13 I1 --- XPVRflg [1,3]? # of subbeams outside the PVR
14 A1 --- Mflg [+CWN] goodness of model fit
15 A1 --- Eflg [+CWX] influence of environment
16 A1 --- Lflg [+CW] lobeshift probability
17 I1 --- LVflg [1,2]? # of low-visibility subbeams
20- 21 I2 h RAh Right Ascension 1950
23- 24 I2 min RAm Right Ascension 1950
26- 31 F6.3 s RAs Right Ascension 1950
33- 37 F5.3 s e_RAs ]0,4[ Right Ascension error
41 A1 --- DE- Declination sign
42- 43 I2 deg DEd Declination 1950
45- 46 I2 arcmin DEm Declination 1950
48- 52 F5.2 arcsec DEs Declination 1950
54- 58 F5.2 arcsec e_DEs ]0,30[ Declination error
60 A1 --- n_S365 [X] X if flux <0.15 Jy
62- 67 F6.3 Jy S365 ]0,80[ 365 MHz flux density
69- 73 F5.3 Jy e_S365 ]0,40[ Internal rms flux error
75 A1 --- SNflg *[XYZ] signal-to-noise flag
77- 80 F4.1 --- Spec ? spectral index
82- 83 F2.1 --- e_Spec ? [0,1[ error in spectral index
86- 89 F4.1 --- Chi2 *? chi-squared flux residual, 2 dof
90 A1 --- u_Chi2 [X] X means value of Chi2 is suspect
91 A1 --- Vstar *[*] * means source may be variable
94- 96 I3 arcsec Sep ? component separation in double model
97 A1 --- --- [ (] field separator
98- 99 I2 arcsec e_Sep ? error in Sep
100 A1 --- --- [)] field separator
102-103 A2 --- Struct *[PAD ] Structure model type
104-105 I2 % q *? Asymetry q parameter for AD model
106 A1 --- --- [(] field separator
107-108 I2 % e_q ? 100xerror in asymmetry parameter q
109 A1 --- --- [)] field separator
111-114 I4 deg Xi [-180,180]? position angle of double
115 A1 --- --- [(] field separator
116-117 I2 deg e_Xi ? error in position angle
118 A1 --- --- [)] field separator
120 A1 --- RAOflg *[*] RA overlap zone flag
121 A1 --- DEOflg *[*] DE overlap zone flag
122 A1 --- --- [(] field separator
123-124 I2 --- KA2 ? second most likely RA lobe
125 A1 --- --- [,] field separator
126-127 I2 --- KD2 ? second most likely Dec lobe
128 A1 --- --- [)] field separator
129 A1 --- RAOZ *[ABCDE] RA overlap zone
130 A1 --- DEOZ *[ABCDEFGHIJK] Dec overlap zone
131-133 A3 --- strp *Observation strip source line taken from
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Note on Strip:
The catalog was originally decomposed in 10 tables table3a to table3j
corresponding to the 10 declination strips:
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Strip Range of
Decl. name
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A -26 [-357,-187]
B -12 [-186,-064]
C -01 [-063,+039]
D +09 [+040,+135]
E +18 [+136,+226]
F +27 [+227,+316]
G +36 [+317,+406]
H +45 [+407,+499]
I +55 [+500,+598]
J +65 [+599,+715]
-----------------------
Note on TXS:
The TXS source name is constructed from the hours and minutes of right
ascension, the sign of declination, and truncated tenths of degrees of
declination: hhmmsddd. Because of a final position system adjustment,
the source name may not agree with the position in the table, but
should be used regardless.
Note on SNflg: the Signal-to-Noise flag is set to:
X when S/N < 4
Y when 4 <= S/N < 5
Z when 5 <= S/N < 7
blank when S/N >=7
Note on Chi2 and Vstar: values of Chi2 are statistically
> 5.99 for 5% of non-variable sources
> 9.21 for 1% of non-variable sources (Vstar set to '*')
>13.82 for 0.1% of non-variable sources
Note on Struct and q:
'P ' = Point model
'D ' = Double model
'AD' = Asymmetric Double model ;
the 'q' asymmetry parameter is then set.
Note on RAOflg and RAOZ:
* means this is one of two versions of this catalog line, because
the source was in an RA overlap zone; the RA zone is then given
in the RAOZ column.
Note on DEOflg and DEOZ:
* means this is one of two versions of this catalog line, because
the source was observed separately in two observation declination
strips; the DE zone is then given in the DEOZ column.
Note on strp: observation strip and segment from which the catalog
line was obtained. For example, in TXS 0000+178, strp=181 means
that the catalog line came from the +18{deg} observation strip,
RA segment 1. Some sources came from Version 6 of the Texas
Survey ('TS6' in strp field) or Version 7 ('TS7' in strp field)
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Byte-by-byte Description of file: simpler.dat
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Bytes Format Units Label Explanations
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1 A1 --- Strip [A-J] Main strip, as in txs.dat file.
3- 11 A9 --- TXS *Source name
13 I1 --- XPVRflg [1,3]? # of subbeams outside the PVR
14 A1 --- Mflg [+CWN] goodness of model fit
15 A1 --- Eflg [+CWX] influence of environment
16 A1 --- Lflg [+CW] lobeshift probability
17 I1 --- LVflg [1,2]? # of low-visibility subbeams
20- 21 I2 h RAh Right Ascension 1950
23- 24 I2 min RAm Right Ascension 1950
26- 31 F6.3 s RAs Right Ascension 1950
33- 37 F5.3 s e_RAs ]0,4[ Right Ascension error
41 A1 --- DE- Declination sign
42- 43 I2 deg DEd Declination 1950
45- 46 I2 arcmin DEm Declination 1950
48- 52 F5.2 arcsec DEs Declination 1950
54- 58 F5.2 arcsec e_DEs ]0,30[ Declination error
60 A1 --- n_S365 [X] X if flux <0.15 Jy
62- 67 F6.3 Jy S365 ]0,80[ 365 MHz flux density
69- 73 F5.3 Jy e_S365 ]0,40[ Internal rms flux error
75 A1 --- SNflg [XYZ] signal-to-noise flag
77- 80 F4.1 --- Spec ? spectral index
82- 83 F2.1 --- e_Spec ? [0,1[ error in spectral index
94- 96 I3 arcsec Sep ? component separation in double model
102 A1 --- Struct *[PD] structure model type
111-114 I4 deg Xi [-180,180]? position angle of double
129 A1 --- RAOZ [ABCDE] RA overlap zone
130 A1 --- DEOZ [ABCDEFGHIJK] Dec overlap zone
131-133 A3 --- strp Observation strip source line taken from
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Note on TXS:
The name is that of the corresponding Survey source line in file txs.dat
Note on Struct:
Point model is 'P'; Double model is 'D';
there are no AD models in the "Simpler models".
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History:
AAS CD-ROM series, Volume 6, 1996.
* At CDS, October 1996:
The original 'table3*' tables were merged into the "txs.dat" file,
and 'table4*' tables into the "simpler.dat" file, but the table
number was inserted in byte one.
References:
Douglas J.N., Bash F.N., Torrence G.W., & Wolfe C., 1980,
Publ. Dept. Astron. Univ. Texas, No 17, October 1980.
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(End) Francois Ochsenbein [CDS] 23-Oct-1996