J/ApJ/409/28 J/ApJ/409/28 Gravitationally Lensed Quasars D Maoz J N Bahcall D P Schneider N A Bahcall S Djorgovski A Gould S Kirhakos R Doxsey G Meylan B Yanny Astrophys. J. 409 28 1993 1993ApJ...409...28M Gravitational lensing QSOs The Snapshot Survey was a search for cases of gravitational lensing among intrinsically-luminous, high-redshift quasars using the Hubble Space Telescope (HST) Planetary Camera (PC). The accompanying ASCII tables summarize the results of the survey.

The Snapshot Survey was a search for cases of gravitational lensing among intrinsically-luminous, high-redshift quasars using the Hubble Space Telescope (HST) Planetary Camera (PC). Bahcall et al. (1992a; hereafter Paper I) described the objectives of the survey, its mode of operation, the sample definition, and the initial results of a small sample. Maoz et al. (1992b, 1993a, 1993b hereafter Papers II, III, and IV) reported results from a progressively larger sample and compared the observed lensing frequency to existing theoretical models. The discovery of a possible sub-arcsecond lens system, the z=3.8 quasar 1208+1011, reported by Maoz et al. (1992a) and Magain et al. (1992), was followed by HST multi-color imaging and spectroscopy as described in Bahcall et al. (1992b) and in Bahcall et al. (1992c), respectively. Star counts based on the Snapshot Survey images are described in Gould, Bahcall, and Maoz (1993). For all objects in the Survey, finding charts and astrometric positions appear in Schneider et al. (1992). The accompanying tables, published in Paper IV, summarize the results of the Snapshot Survey for gravitationally lensed quasars. Table_1a.dat combines the results from Papers II, III, and IV into one list ordered by R.A. These tables have more accurately measured quasar magnitudes, and minor corrections have been made in some of the entries listed in the tables in previous papers, so that the present list superseded previous data summaries. Table_1b.dat lists the Paper I observations in the same format as table_1a.dat. Some of the exposures are only 120s (program 3034) and about half of the initial exposures were through the F785LP filter (similar to I), rather than the F555W filter. We have included in table_1b.dat only quasars that were not subsequently re-observed. These files can be merged without repetition. Exposures through the F785LP filter are marked with an "I" in the V_obs column.

name Quasar name, without prefixes (1950 coor.) blank indicates repeated observation of preceding quasar --- altna Veron name --- date Date Observed --- HST HST Program Number --- chip PC chip showing object --- XY Central coordinate of quasar The coordinate of the center of the mosaic (not the chip) is 1, 1 pix off Offset from designated position on chip 6 arcsec drift Drift rate (g = guided exposure) marcsec V_obs Observed V (I indicates F785LP filter) mag V_ver Magnitude tabulated by Veron mag disc Discovery method R = radio selected C = selected by color S = Emission lines in spectrum O = Other (e.g. variability) --- redsh Redshift km/sec M Absolute magnitude mag note Notes An See "Notes on Individual Objects" in Paper n of Snapshot series. B Guided exposure, but quasar offset by $12"$ for unknown reasons. C Quasar image split between PC-6 and PC-7. D Quasar not verified to be in the field of view, but likely present based on brightness and/or expected absence of additional objects (see paper IV). F Possibly some point-spread function asymetry at $0.1-0.2"$ scales. E Quasar just off PC-8. G Identification uncertain. H Quasar image split between PC-7 and PC-8. J Poor fine-lock guiding attempt; multiple/trailed images. K Quasar image split between PC-5 and PC-6. L Cosmic ray event on or near quasar image core. --- D. Maoz Inst. Adv. Studies N.G. Roman NSSDC/ADC 1994Aug04 J_ApJ_409_28.xml