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1996AJ....111.1945Douglas+

CDROM/AJ/V111/P1945 Texas Survey (Douglas+ 1996)


The Texas Survey of Radio Sources Covering -35.5 deg < Dec. < 71.5 deg at 365 MHz

James N. Douglas, Frank N. Bash, F. Arakel Bozyan, Geoffrey W. Torrence & Chip Wolfe


Abstract:

We present the Texas Survey of discrete radio sources between -35.5 deg and 71.5 deg declination (B1950), which was carried out at 365 MHz 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 0.4 Jy and 80% complete at 0.25 Jy, is nearly free from spurious sources, and has a lobeshift incidence which is reasonably described by quality flags associated with each source.
File Summary:
----------------------------------------------------------------------------
File Name    Lrecl    Records   Explanations
----------------------------------------------------------------------------
table3a.dat    133       9405   Texas Survey, -26 deg strip: [-357,-187]
table3b.dat    133       8533   Texas Survey, -12 deg strip: [-186,-064]
table3c.dat    133       8022   Texas Survey, -01 deg strip: [-063,+039]
table3d.dat    133       7772   Texas Survey, +09 deg strip: [+040,+135]
table3e.dat    133       7437   Texas Survey, +18 deg strip: [+136,+226]
table3f.dat    133       6302   Texas Survey, +27 deg strip: [+227,+316]
table3g.dat    133       6367   Texas Survey, +36 deg strip: [+317,+406]
table3h.dat    133       5084   Texas Survey, +45 deg strip: [+407,+499]
table3i.dat    133       4516   Texas Survey, +55 deg strip: [+500,+598]
table3j.dat    133       3403   Texas Survey, +65 deg strip: [+599,+715]
table4a.dat    133       2110   Simpler Models, -26 deg strip
table4b.dat    133       2045   Simpler Models, -12 deg strip
table4c.dat    133       1918   Simpler Models, -01 deg strip
table4d.dat    133       1950   Simpler Models, +09 deg strip
table4e.dat    133       1922   Simpler Models, +18 deg strip
table4f.dat    133       1329   Simpler Models, +27 deg strip
table4g.dat    133       1666   Simpler Models, +36 deg strip
table4h.dat    133       1159   Simpler Models, +45 deg strip
table4i.dat    133        962   Simpler Models, +55 deg strip
table4j.dat    133        697   Simpler Models, +65 deg strip
----------------------------------------------------------------------------

Byte-by-byte Description of file: table3a.dat table3b.dat table3c.dat
  table3d.dat table3e.dat table3f.dat table3g.dat table3h.dat table3i.dat
  table3j.dat
----------------------------------------------------------------------------
   Bytes Format  Units   Label      Explanations
-----------------------------------------------------------------------------
   1      1X      ---     ---      Blank
   2      A1      ---     Aflg     [ *] * means simpler model(s) exist
   3- 11  A9      ---     Source  *Source name
  12      1X      ---     ---      Blank
  13      A1      ---     XPVRflg  [ 123] # 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      A1      ---     LVflg    [ 12]  # of low-visibility subbeams
  18- 19  2X      ---     ---      blank
  20- 21  I2      h       RAh      Right Ascension 1950
  22      1X      ---     ---      blank
  23- 24  I2      min     RAm      Right Ascension 1950
  25      1X      ---     ---      blank
  26- 31  F6.3    s       RAs      Right Ascension 1950
  32      1X      ---     ---      blank
  33- 37  F5.3    s       e_RA     ]0,4[  Right Ascension error
  38- 40  3X      ---     ---      blank
  41      A1      ---     DE-      Declination sign
  42- 43  I2      deg     DEd      Declination 1950
  44      1X      ---     ---      blank
  45- 46  I2      arcmin  DEm      Declination 1950
  47      1X      ---     ---      blank
  48- 52  F5.2    arcsec  DEs      Declination 1950
  53      1X      ---     ---      blank
  54- 58  F5.2    arcsec  e_DE     ]0,30[ Declination error
  59      1X      ---     ---      blank
  60      A1      ---     n_Flux   [ X] X if flux <0.15 Jy
  61      1X      ---     ---      blank
  62- 67  F6.3    Jy      Flux     ]0,80[ 365 MHz flux density
  68      1X      ---     ---      blank
  69- 73  F5.3    Jy      e_Flux   ]0,40[ Internal rms flux error
  74      1X      ---     ---      blank
  75      A1      ---     SNflg    [ YZ] signal-to-noise flag
  76      1X      ---     ---      blank
  77- 80  F4.1    ---     Spec     []? spectral index
  81      1X      ---     ---      blank
  82- 83  F2.1    ---     e_Spec   [0,1[?  error in spectral index
  84- 85  2X      ---     ---      blank
  86- 89  F4.1    ---     Var      []? chi-squared flux residual, 2 dof
  90      A1      ---     Vflg     [ X] X means value of var is suspect
  91      A1      ---     Vstar    [ *] * means source may be variable
  92- 93  2X      ---     ---      blank
  94- 96  I3      arcsec  Sep      []?  component separation in double model
  97      1X      ---     ---      [ (] field separator
  98- 99  I2      arcsec  e_Sep    []? error in isep
 100      1X      ---     ---      [ )] field separator
 101      1X      ---     ---      blank
 102-105  A4      ---     ModStr  *structure model type
 106      1X      ---     ---      [ (] field separator
 107-108  I2      ---     e_q      []? 100xerror in asymmetry parameter q
 109      1X      ---     ---      [ )] field separator
 110      1X      ---     ---      blank
 111-114  I4      deg     Xi       []? position angle of double
 115      1X      ---     ---      [ (] field separator
 116-117  I2      deg     e_Xi     []? error in positin angle
 118      1X      ---     ---      [ )] field separator
 119      1X      ---     ---      blank
 120      A1      ---     RAOflg  *[ *] RA overlap zone flag
 121      A1      ---     DEOflg  *[ *] DE overlap zone flag
 122      1X      ---     ---      [ (] field separator
 123-124  I2      ---     KA2      []? second most likely RA lobe
 125      1X      ---     ---      [ ,] field separator
 126-127  I2      ---     KD2      []? second most likely Dec lobe
 128      1X      ---     ---      [ )] 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
-----------------------------------------------------------------------------

Notes on file: table3a.dat table3b.dat table3c.dat
  table3d.dat table3e.dat table3f.dat table3g.dat table3h.dat table3i.dat
  table3j.dat
----------------------------------------------------------------------------
Source:
  The 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.

ModStr:
  Point model is ' P'; Double model is ' D', and asymmetric double is
  'ADnn' where nn=100 x q, the asymmetry parameter.

RAOflg:
  * means this is one of two versions of this catalog line, because
  the source was in an RA overlap zone.

DEOflg:
  * means this is one of two versions of this catalog line, because
  the source was observed separately in two observation declination
  strips.
----------------------------------------------------------------------------

Byte-by-byte Description of file: table4a.dat table4b.dat table4c.dat
  table4d.dat table4e.dat table4f.dat table4g.dat table4h.dat table4i.dat
  table4j.dat
-----------------------------------------------------------------------------
   Bytes Format  Units   Label      Explanations
----------------------------------------------------------------------------
  1-  2  2X      ---     ---      Blank
  3- 11  A9      ---     Source  *Source name
 12      1X      ---     ---      Blank
 13      A1      ---     XPVRflg  [ 12] # of subbeams outside the PVR
 14      A1      ---     Mflg     [+] goodness of model fit
 15      A1      ---     Eflg     [+CWX] influence of environment
 16      A1      ---     Lflg     [+CW]  lobeshift probability
 17      A1      ---     LVflg    [ 12]  # of low-visibility subbeams
 18- 19  2X      ---     ---      blank
 20- 21  I2      h       RAh      Right Ascension 1950
 22      1X      ---     ---      blank
 23- 24  I2      min     RAm      Right Ascension 1950
 25      1X      ---     ---      blank
 26- 31  F6.3    s       RAs      Right Ascension 1950
 32      1X      ---     ---      blank
 33- 37  F5.3    s       e_RA     ]0,4[  Right Ascension error
 38- 40  3X      ---     ---      blank
 41      A1      ---     DE-      Declination 1950 sign
 42- 43  I2      deg     DEd      Declination 1950
 44      1X      ---     ---      blank
 45- 46  I2      arcmin  DEm      Declination 1950
 47      1X      ---     ---      blank
 48- 52  F5.2    arcsec  DEs      Declination 1950
 53      1X      ---     ---      blank
 54- 58  F5.2    arcsec  e_DE     ]0,30[ Declination error
 59      1X      ---     ---      blank
 60      A1      ---     n_Flux   [ X] X if flux <0.15 Jy
 61      1X      ---     ---      blank
 62- 67  F6.3    Jy      Flux     ]0,80[ 365 MHz flux density
 68      1X      ---     ---      blank
 69- 73  F5.3    Jy      e_Flux   ]0,40[ Internal rms flux error
 74      1X      ---     ---      blank
 75      A1      ---     SNflg    [ YZ] signal-to-noise flag
 76      1X      ---     ---      blank
 77- 80  F4.1    ---     Spec     []? spectral index
 81      1X      ---     ---      blank
 82- 83  F2.1    ---     e_Spec   [0,1[ ?  error in spectral index
 84- 93  10X     ---     ---      blank (Var,Vflg,Vstar in Table 3)
 94- 96  I3      arcsec  Sep      []?  component separation in double model
 97-101  5X      ---     ---      blank (e_Sep in Table 3)
102-105  A4      ---     ModStr  *structure model type
106-110  5X      ---     ---      blank (e_q in Table 3)
111-114  I4      deg     Xi       []? position angle of double
115-128  14X     ---     ---      blank (e_Xi,RAOFlg,DEOFlg,KA2,KD2 in Table 3)
129      A1      ---     RAOZ     [ ABCDE] RA overlap zone
130      A1      ---     DEOZ     [ ABCDEFGHIJK] DE overlap zone
131-133  A3      ---     Strp     Observation strip source line taken from
-----------------------------------------------------------------------------
Notes on file: table4a.dat table4b.dat table4c.dat
  table4d.dat table4e.dat table4f.dat table4g.dat table4h.dat table4i.dat
  table4j.dat
-----------------------------------------------------------------------------
Source:
  The name is that of the corresponding Survey source line in Table 3.

ModStr:
  Point model is '   P'; Double model is '   D'; there are no AD
  models in the "Simpler models".
---------------------------------------------------------------------------

============================================================================
(End)

Flux density

The survey flux density scale is defined by the adopted 365 MHz flux density of 582 flux calibrators: sources not initially known to be time variable at meter wavelengths, and whose survey catalog enters have correct position and structure model.

The basis for the Texas Survey flux densities is a slightly modified version of the flux scale developed by Wills (1973, Ap.J. 180, 335), here referred to as the "BW scale". The BW scale was recreated from basic flux data, rereduced and modified to reflect an assumed frequency-independent secular decrease of the flux density of Cas A of 0.8 % per year, rather than the 1.3 % oer year originally used Wills. The resultant scale (TXS for Texas Survey) is about 2% below BW at 365 MHz. For comparison purposes, a reduction was also done using the Cas A spectrum adopted by Baars et al. (1977), here denoted "BA". At 365 MHz, the relationship between the three scales is
S(TXS) = 0.9828S(BW) = 0.9607S(BA)
Evaluation of the TXS flux scale at 408 MHz showns it to be identical to the absolute flux scale defined by Wyllie (1969a, MNRAS, 142, 229) (1969b, PASAu, 1, 234) and used for the Molonglo 408 MHz data.