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J/ApJ/673/78   VLBI suvey around B0218+357 at 90cm           (Lenc+, 2008)

A deep, high-resolution survey of the low-frequency radio sky. Lenc E., Garrett M.A., Wucknitz O., Anderson J.M., Tingay S.J. <Astrophys. J., 673, 78-95 (2008)> =2008ApJ...673...78L
ADC_Keywords: Radio sources ; VLBI Keywords: galaxies: active - quasars: individual (QSO B0218+357, J0226+3421) - radiation mechanisms: general - techniques: interferometric Abstract: We report on the first wide-field, very long baseline interferometry (VLBI) survey at 90cm. The survey area consists of two overlapping 28deg2 fields centered on the quasar J0226+3421 and the gravitational lens B0218+357. A total of 618 sources were targeted in these fields, based on identifications from Westerbork Northern Sky Survey (WENSS) data. Of these sources, 272 had flux densities that, if unresolved, would fall above the sensitivity limit of the VLBI observations. A total of 27 sources were detected as far as 2° from the phase center. The results of the survey suggest that at least 10% of moderately faint (S∼100mJy) sources found at 90 cm contain compact components smaller than ∼0.1"-0.3" and stronger than 10% of their total flux densities. Description: A VLBI observation of the gravitational lens B0218+357 was made on 11 November 2005 using all 10 NRAO Very Long Baseline Array (VLBA) antennas, the Westerbork Synthesis Radio Telescope (WSRT) as a phased array, and the Jodrell Bank (JB) 76m Lovell Telescope. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 70 103 Astrometry and photometry at 324 MHz for Field 1 (centered on J0226+3421) targets table3.dat 70 196 Astrometry and photometry at 324 MHz for Field 2 (centered on B0218+357) targets table4.dat 56 28 Source and image characteristics and astrometric errors
See also: VIII/62 : The Westerbork Northern Sky Survey (WENSS) (Leiden, 1998) Byte-by-byte Description of file: table[23].dat
Bytes Format Units Label Explanations
1- 4 F4.2 deg Ann1 Annulus from field center (lower bound) 5 A1 --- --- [-] 6- 9 F4.2 deg Ann2 Annulus from field center (upper bound) 11- 22 A12 --- WENSS WENSS source designation, BHHMM.m+DDMMA 23 A1 --- m_WENSS [AB] Multiplicity index on WENSS 25 A1 --- n_WENSS [WV] W=WENSS target source, V=VLBI detection 27- 28 I2 h RAh Right ascension (J2000.0) 30- 31 I2 min RAm Right ascension (J2000.0) 33- 39 F7.4 s RAs Right ascension (J2000.0) 41 A1 --- DE- Declination sign (J2000.0) 42- 43 I2 deg DEd Declination (J2000.0) 45- 46 I2 arcmin DEm Declination (J2000.0) 48- 53 F6.3 arcsec DEs Declination (J2000.0) 55- 58 I4 mJy Speak Peak flux density per solid beam angle at 90cm (in mJy/beam) 61- 64 I4 mJy Sint Integrated flux at 90cm 66- 70 F5.2 --- SI ? Spectral index alpha estimated from the WENSS and NVSS integrated flux densities where available
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 12 A12 --- WENSS WENSS designation (excepted 3C 84) 13 A1 --- m_WENSS Multiplicity index on Source 15 I1 --- Fld [1/2]? Field number 17- 20 F4.2 deg Dpc ? Distance of the source from the phase center of the observed field 22- 24 I3 mas Beam1 Beam size 25 A1 --- --- [x] 26- 28 I3 mas Beam2 Beam size 30- 32 I3 deg PA [-90/90] Beam position angle 34- 36 F3.1 mJy noise 1σ residual noise after the source model has been subtracted from the image (mJy/beam) 38- 40 A3 --- Ref Reference for positions (1) 42- 47 F6.3 arcsec DE Measured offset of the VLBI source peak from the position listed in reference 49- 51 I3 deg thetaE Position angle of the VLBI source peak in relation to the position listed in reference 53- 56 F4.1 --- ds Measured offset of the VLBI source peak in relation to the position listed in reference in terms of the 1σ astrometric precision σp
Note (1): References as follows: B02 = 2.3/8.3GHz VLBA, Beasley et al., 2002, Cat. J/ApJS/141/13 C98 = 1.4GHz VLA, Condon et al., 1998, Cat. VIII/65 D96 = 365MHz Texas interferometer, Douglas et al., 1996, Cat. VIII/42 P92 = 8.4GHz VLA, Patnaik et al., 1992, Cat. VIII/60 R94 = 1.4GHz VLA, Rottgering et al., 1994, Cat. J/A+AS/108/79
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 07-Apr-2010
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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