J/ApJS/98/1 J/ApJS/98/1 First Caltech-Jodrell Bank VLBI Survey. I. A G Polatidis P N Wilkinson W Xu A C S Readhead T J Pearson G B Taylor R C Vermeulen Astrophys. J. Suppl. Ser. 98 1 1995 1995ApJS...98....1P J/ApJS/98/33 : First Caltech-Jodrell Bank VLBI Survey. II (Thakkar+ 1995) J/ApJS/99/297 : First Caltech-Jodrell Bank VLBI Survey. III (Xu+ 1995) J/ApJS/95/345 : Second Caltech-Jodrell Bank VLBI Survey. I. (Taylor+ 1994) J/ApJS/100/1 : Second Caltech-Jodrell Bank VLBI Survey. II (Henstock+ 1995) QSOs Radio sources VLBI quasars: general radio continuum: galaxies surveys techniques: interferometric We present the first results from the first Caltech-Jodrell Bank VLBI survey (the CJ1 survey). The CJ1 sample includes 135 radio sources with total flux density 1.3Jy>S_6cm>=0.7Jy, declination delta_1950>=35deg, and Galactic latitude |b^II|>10deg. It extends the flux density limit of the complete "PR" sample studied by Pearson & Readhead from 1.3 to 0.7Jy and increases the total number of sources from 65 to 200. The complete survey includes VLBI images at both lambda-18 and 6cm of all objects in the extended sample that have cores strong enough to be mapped with the Mark II VLBI system. These images provide a large enough sample to study, for example, the variety of morphologies exhibited by compact radio sources, cosmological evolution, superluminal motion, and misalignment between parsec-scale and kiloparsec-scale radio structures. In this paper we present lambda-18cm VLBI observations of 56 CJ1 and 31 PR sources made in 1990-1991, including images of 82 sources. The observations were made with a "snapshot" technique in which each source was observed in three 20-30-minute scans using an array of 12-16 antennas. The images have resolution 3-10mas and dynamic range greater than 100:1. Later papers in the series will present the remaining lambda-18cm observations, the lambda-6cm observations, and the analysis and interpretation of the results.

CJ1 B1950 source name according to IAU convention --- RAh Right ascension, J2000.0 h RAm Right ascension, J2000.0 min RAs Right ascension, J2000.0 s DEd Declination, J2000.0 deg DEm Declination, J2000.0 arcmin DEs Declination, J2000.0 Positions specified with a precision of 0.01" are from the Jodrell Bank- VLA Astrometric Survey (Patnaik et al. 1992MNRAS.254..655P, Tables 2 and 4; and unpublished observations); the remaining positions have been compiled from a variety of publications via the NASA Extragalactic Database (NED). arcsec S11cm Total flux density at 11 cm Total flux density at 11cm from Pauliny-Toth et al. 1978AJ.....83..451P Jy S6cm Total flux density at 6 cm Total flux density at 6cm from Kuhr et al. 1981AJ.....86..854K Jy S2.8cm Total flux density at 2.8 cm Total flux density at 3.6cm from Kuhr et al. 1981AJ.....86..854K Jy ID Optical identification Optical identification: BL - BL Lac object; EF - Empty Field; G - Galaxy; Q - Quasar; SO - Stellar object. --- V Apparent V magnitude mag n_z 'f' - featureless spectrum, '>' - limit --- z Redshift See notes to Table 1 in the printed paper for references. --- OBSy Date of VLBI observations (year) yr OBSm Date of VLBI observations (month) --- n_OBSy Notes on observation date Parentheses indicate that the source was observed but not mapped; in three cases (marked with an asterisk) this is because the a priori position assumed for correlations was wrong, while in the other cases the source was too heavily resolved. A blank field indicates that the source was not observed because it does not contain a compact component strong enough for detection with Mark-II VLBI. --- r_OBS Reference to published observation 1: Xu et al. 1994AJ....108..395X 2: Stickel & Khuer 1994 <J/A+AS/103/349> 3: Stickel, Meisenheimer & Khuer 1994 <<J/A+AS/105/211> 4: Spinrad et al. 1985 <J/PASP/97/932> 5: Browne et al. 1993MNRAS.263L..32B 6: Henstock, Browne & Wilkinson 1995 <J/ApJS/100/1> 7: Jackson 1989 (Ph.D. thesis, Univ. of Manchester) 8: Palomar Observatory Sky Survey 9: Hewitt & Burbidge 1993 <VII/158> 10: Eckart et al. 1987A&AS...67..121E 11: Sanghera 1992 (Ph.D. thesis, Univ. of Manchester) 12: Fanti et al. 1985A&A...143..292F 13: Dallacasa et al. 1995A&A...295...27D 14: Foulsham 1989 (M.Sc. thesis, Univ. of Manchester) 15: Jones et al. 1986ApJ...305..684J 16: Dallacasa et al. 1990 (in Compact Steep-Spectrum and GHz-peaked Spectrum Radio Sources, ed. C. Fanti, D. Fanti. C.P. O'Dea & R.T. Schilizzi, Bologna: Consiglio Nazionale delle Ricerche, 77 17: Sanghera 1989 (M.Sc. thesis, Univ. of Manchester) 18: Lawrence, Zucker, Readhead, Unwin, Pearson & Xu, 1995, ApJS, submitted --- CJ1 B1950 source name according to IAU convention --- RAh Right ascension, J2000.0 h RAm Right ascension, J2000.0 min RAs Right ascension, J2000.0 s DEd Declination, J2000.0 deg DEm Declination, J2000.0 arcmin DEs Declination, J2000.0 Positions specified with a precision of 0.01" are from the Jodrell Bank- VLA Astrometric Survey (Patnaik et al. 1992MNRAS.254..655P, Tables 2 and 4; and unpublished observations); the remaining positions have been compiled from a variety of publications via the NASA Extragalactic Database (NED). arcsec S11cm Total flux density at 11 cm Total flux density at 11cm from Pauliny-Toth et al. 1978AJ.....83..451P Jy S6cm Total flux density at 6 cm Total flux density at 6cm from Kuhr et al. 1981AJ.....86..854K Jy S2.8cm Total flux density at 2.8 cm Total flux density at 3.6cm from Kuhr et al. 1981AJ.....86..854K Jy ID Optical identification Optical identification: BL - BL Lac object; G - Galaxy; Q - Quasar --- Vmag Apparent V magnitude mag z Redshift from Lawrence et al. Lawrence, Zucker, Readhead, Unwin, Pearson & Xu, 1995, ApJS, submitted --- OBSy Date of VLBI observations (year) yr OBSm Date of VLBI observations (month) --- CJ1 B1950 source name according to IAU convention --- OBSy Date of VLBI observation (year) yr OBSm Date of VLBI observation (month) --- Samp VLBI sample (CJ1 or PR) source belongs to --- a18cmn FWHM of major axis of the restoring beam mas b18cmn FWHM of minor axis of the restoring beam mas PA18cmn Position angle of major axis, north through east deg S18cmn Peak flux density, naturally weighted map Data are in mJy/beam mJy e_S18cmn Off source rms, naturally weighted map mJy a18cmt FWHM of major axis of tapered map restoring beam mas b18cmt FWHM of minor axis of tapered map restoring beam mas PA18cmt Position angle of major axis, N through E deg S18cmt Peak flux density, tapered map mJy e_S18cmt Off source rms, tapered map mJy CJ1 B1950 source name according to IAU convention --- S Flux density of component Jy Rad Radius of component Radius of component, measured from position of first component mas Theta Angle to component Angle to component, measured north through east from the position of the first component deg a FWHM of major axis of component mas b/a Axial ratio of major to minor axis, b/a --- Phi Position angle of major axis, north through east deg Chi2 Chi-squared between the model and the self-calibrated UV-data --- CDS 1996Oct14AAS CD-ROM series, Volume 4, 1995 Lee Brotzman [ADS] 10-May-95 J_ApJS_98_1.xml