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J/ApJS/136/265  Monitoring compact radio sources at 2.5 + 8.2GHz (Lazio+, 2001)
A dual-frequency, multiyear monitoring program of compact radio sources.
    Lazio T.J.W., Waltman E.B., Ghigo F.D., Fiedler R.L., Foster R.S.,
    Johnston K.J.
   <Astrophys. J. Suppl. Ser. 136, 265 (2001)>
   =2001ApJS..136..265L
ADC_Keywords: Radio sources ; Redshifts

Keywords: radio continuum: general - scattering - surveys


Abstract:
    We present light curves for 149 sources monitored with the Green Bank
    Interferometer. The light curves are at two radio frequencies
    (approximately 2.5 and 8.2GHz) and range from 3 to 15yr in length,
    covering the interval 1979-1996, and have a typical sampling of one
    flux density measurement every 2 days.

    Observations were made on a 2.4km baseline. Dual circular
    polarization was recorded over a 35MHz bandwidth at two frequencies
    in the S and X frequency bands. Until 1989 August (1989.7), the
    frequencies were 2.7GHz (S band) and 8.1GHz (X band); in 1989
    September cryogenic receivers were installed, and the frequencies
    changed to 2.25GHz (S band) and 8.3GHz (X band).

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat       168      149   Sources Monitored with the Green Bank Interferometer
gbi/*             78      149   Fluxes observed (time series)


See also:
  J/ApJS/128/17 : VLBA obs. of radio reference frame sources. III. (Fey+, 2000)
  http://ese.nrl.navy.mil/GBI : Navy's Extragalactic Source Monitoring Program


Byte-by-byte Description of file: table1.dat

   Bytes Format Units   Label     Explanations

   1-  9  A9    ---     Name      Source name (5)
      10  A1    ---     f_Name    Name variation (5)
  11- 13  I3    deg     GLON      Galactic longitude
  15- 17  I3    deg     GLAT      Galactic latitude
  19- 24  F6.1  yr      Obs0      Start of the observation
  26- 31  F6.1  yr      Obs1      End of the observation
  33- 37  F5.2  Jy      S2GHz     Mean 2.5GHz flux density (1)
  39- 43  F5.2  Jy      S8GHz     Mean 8.2GHz flux density (1)
  45- 48  A4    ---     Type      Source identification: Quasar (Q), Galaxy (G),
                                     BL Lac object (BL), star (*)
  50- 54  A5    ---     SF        Structure indices (3)
  56- 60  F5.3  ---     z         ? Redshift
      61  A1    ---     u_z       [?] Indicates an uncertain redshift
  63- 66  F4.1  mag     Vmag      ? The apparent V band magnitude
      68  A1    ---     ---       [i]
  69- 70  I2    ---     r_Name    ? References for identification (4)
      71  A1    ---     ---       [s]
  72- 73  I2    ---     r_S2GHz   ? References for VLBI structure (4)
      74  A1    ---     ---       [z]
  75- 76  I2    ---     r_z       ? References for redshift (4)
      77  A1    ---     ---       [m]
  78- 79  I2    ---     r_Vmag    ? References for optical magnitude (4)
  81-168  A88   ---     AName     Alternate name

Note (1): Over the interval 1989.7-1994.

Note (3): Measure of how compact the source is on milliarcsecond scales
    and defined by Charlot (1990AJ.....99.1309C). A source with a
    structure index of 1 is relatively compact, having 90% or more of its
    flux density in a single component, while a structure index of 4
    indicates a relatively extended source, typically having two or more
    components of approximately equal flux density. Structure indices are
    taken from Fey & Charlot (1997ApJS..111...95F) and Fey & Charlot
    (2000, Cat. J/ApJS/128/17), who determined the structure indices
    from the contribution of the sources' structures to interferometric
    group delays in VLBI observations.
Note (4): References as follows:
      0 = Condon et al. (1983AJ.....88...20C)
      1 = Hewitt & Burbidge (1991ApJS...75..297H, Cat. VII/178)
      2 = Hewitt & Burbidge (1993ApJS...87..451H, Cat. VII/158)
      3 = Stickel & Kuhr (1994A&AS..103..349S, Cat. III/175)
      4 = Stickel, Meisenheimer, Kuhr (1994, Cat. J/A+AS/105/211)
      5 = Stickel & Kuhr (1996, Cat. J/A+AS/115/1)
      6 = Drinkwater et al. (1996A&AS..115....1S, Cat. VIII/34)
      7 = Fey & Charlot (1997ApJS..111...95F)
      8 = Veron-Cetty & Veron (2000ESOSR..19....1V, see cat. VII/224)
      9 = Fey & Charlot (2000, Cat. J/ApJS/128/17)
     10 = de Vries et al. (2000A&AS..143..181D)
     11 = Spinrad et al. (1985, Cat. J/PASP/97/932)
     12 = Zacharias et al. (1999AJ....118.2511Z)
Note (5): 4 sources (marked with the '*') have a name slighlty different
     in the sub-directory gdb. These names are flagged with an asterisk
     in byte 10 (added at CDS) and concern:
     1038+528A/1038+528 ; 1547+507/1547+508; 
     2007+777/2007+776 ;  2307+106/2307+107


Byte-by-byte Description of file: gbi/*

   Bytes Format Units  Label   Explanations

   4- 12  F9.3  d      MJD     Epoch of observation (JD-2400000.0 or 2400000.5?)
  15- 22  F8.3  yr     Epoch   Epoch of observation (Besselian year)
  27- 32  F6.3  ---    LHA     Unexplained parameter
  37- 42  F6.3  Jy     S2GHz   ?=-1 Flux observed at 2GHz
                                   (2.7GHz before 1989.7, 2.25GHz after)
  47- 52  F6.3  Jy     S8GHz   ?=-1 Flux observed at 8GHz
                                    (8.1GHz before 1989.7, 8.3GHz after)
  57- 62  F6.2  ---    SI      ?=-10 Spectral index between 2 and 8GHz
                                     (S(ν)∝να
  65- 70  F6.3  Jy    e_S2GHz  ?=0 Mean error on S2GHz
  73- 78  F6.3  Jy    e_S8GHz  ?=0 Mean error on S8GHz


History:
  * 14-Jan-2002: From electronic version of the journal
  * 01-Dec-2010: Added time series subdirectory,
       from http://ese.nrl.navy.mil/GBI/

References:
    Fiedler et al., Paper I     1987ApJS...65..319F
    Waltman et al.,             1991ApJS...77..379W
(End)                    Greg Schwarz [AAS], Patricia Bauer [CDS]    14-Jan-2002