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J/AJ/133/2357      Relativistic jets in the RRFID database        (Piner+, 2007)

Relativistic jets in the Radio Reference Frame Image Database. I. Apparent speeds from the first 5 years of data. Piner B.G., Mahmud M., Fey A.L., Gospodinova K. <Astron. J., 133, 2357-2388 (2007)> =2007AJ....133.2357P
ADC_Keywords: Radio sources ; QSOs ; Active gal. nuclei ; Morphology Keywords: galaxies: active - galaxies: jets - radio continuum: galaxies Abstract: We present the results of an analysis of relativistic jet apparent speeds from VLBI images in the Radio Reference Frame Image Database (RRFID). The images are snapshot VLBI images at 8 and 2GHz using the VLBA, plus up to 10 additional antennas that provide global VLBI coverage. We have analyzed the 8GHz images from the first 5 years of the database (1994-1998), for all sources observed at three or more epochs during this time range. This subset comprises 966 images of 87 sources. The sources in this subset have an average of 11 epochs of observation over the years 1994-1998, with the best-observed sources having 19 epochs. About half of the sources in this RRFID kinematic survey have not been previously studied with multi-epoch VLBI observations. We have measured apparent speeds for a total of 184 jet components in 77 sources, of which the best-measured 94 component speeds in 54 sources are used in the final analysis. Description: Observations were made using the 10 antennas of the VLBA of the National Radio Astronomy Observatory (NRAO),7 along with an array consisting of up to seven geodetic antennas. Eight intermediate frequencies (IFs) were recorded simultaneously, each 8MHz wide, with four at S band (2.24, 2.27, 2.36, and 2.38GHz) and four at X band (8.41, 8.48, 8.79, and 8.90GHz) for a total bandwidth of 32MHz in each frequency band. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 32 87 Sources in the RRFID kinematic survey table3.dat 77 2579 Gaussian Models table4.dat 44 184 Apparent Component Speeds
See also: J/AJ/110/880 : Radio reference frame (Johnston+ 1995) J/ApJS/128/17 : VLBA obs. of radio reference frame sources. III. (Fey+, 2000) J/AJ/127/3609 : VLBI observations of southern ICRF sources (Ojha+, 2004) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 8 A8 --- IERS IAU name (HHMM+DDd, IERS BHHMM+DDd in Simbad) 10- 17 A8 --- OName Other name 19- 20 I2 --- Nep Number of epochs observed 22- 26 A5 --- Class Optical class (1) 28- 32 F5.3 --- z ?=- Redshift
Note (1): Optical class from Veron-Cetty & Veron (2003, Cat. VII/235) as follows: Q = quasar B = BL Lac object G = galaxy HP = high polarization U = unidentified
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 8 A8 --- IERS IAU name (HHMM+DDd, IERS BHHMM+DDd in Simbad) 10- 15 F6.3 Jy S Component flux density at 8GHz 17- 22 F6.3 mas Rad Radial position of component center 24- 29 F6.1 deg PA [-180/180] Position angle of component center (1) 31- 35 F5.3 mas a Full-width at half maximum size of component 37- 41 F5.3 --- b/a Axial ratio of component 43- 47 F5.1 deg PAMA Position angle of major axis; if an elliptical component (1) 49 I1 --- Type [1] DIFMAP component type (1 = Gaussian) 51- 57 F7.2 yr Epoch Epoch of observation 59- 60 I2 --- Comp ?=99 Component ID (2) 62- 66 F5.2 mas aBeam Beam major axis (3) 68- 71 F4.2 mas bBeam Beam minor axis (3) 73- 77 F5.1 deg PABeam Beam position angle (1,3)
Note (1): All position angles are measured from north through east. Note (2): The core is identified as component 0, and other jet components are identified as components 1-6, from the outermost component inward. An ID of '99' indicates a flagged component not used in the analysis. Note (3): Beam parameters are computed using natural weighting specifically 'uvweight = 0,-1' in DIFMAP.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 8 A8 --- IERS IAU name (HHMM+DDd, IERS BHHMM+DDd in Simbad) 10 I1 --- Comp [1/6] Component ID 12- 17 F6.3 mas/yr mu Proper motion 19- 23 F5.3 mas/yr e_mu Uncertainty in mu 25- 30 F6.2 --- beta Apparent speed in units of the speed of light 32- 36 F5.2 --- e_beta Uncertainty in beta 38 I1 --- xi The xi value (1) 40 A1 --- DC [Y/N] Distinct component (2) 42 A1 --- Qual [EFGP] Overall quality code (3) 44 A1 --- 2cm [Y/N] In a 2cm (15GHz) survey (4)
Note (1): Error bars on component positions were computed as a fraction 1/2ξ of the beam size, where ξ was a function of the average flux of the component, see Section 4.1. Note (2): Whether or not the component is a distinct feature. Y=Yes, N=No. Note (3): Criteria definitions as follows: E = Excellent; for motions that satisfy all three of the criteria. G = Good; for motions that satisfy any two of the criteria. F = Fair; for motions that satisfy only one of the criteria. P = Poor; for motions that do not satisfy any of the criteria, or for motions where the uncertainty in the fitted proper motion is >0.15mas/yr (except for the ≥5σ cases mentioned in the text. Note (4): Whether or not the source has an apparent speed measured from the 2cm survey (Kellermann et al., 2004, cat. J/ApJ/609/539). Y=Yes, N=No.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 01-Apr-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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