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J/ApJ/409/28 Gravitationally Lensed Quasars (Maoz + 1993)
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The Hubble Space Telescope Snapshot Survey. IV A Summary of the Search for
Gravitationally Lensed Quasars
Maoz D., Bahcall J.N., Schneider D.P., Bahcall N.A., Djorgovski S.,
Gould A., Kirhakos S., Doxsey R., Meylan G., Yanny B.
<Astrophys. J. 409, 28 (1993)>
=1993ApJ...409...28M
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ADC_Keywords: QSOs ; Gravitational lensing
Abstract:
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.
Introduction:
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papers, so that the present list superseded previous data summaries.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.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table_1a.dat 81 507 Summary of Full Program Observations
table_1b.dat 81 52 Summary of Successful Pilot Observations
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Byte-by-byte Description of file: table_1a.dat table_1b.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- name *Quasar name, without prefixes (1950 coor.)
12- 19 A8 --- altna Veron name
21- 28 A8 --- date !Date Observed
30- 33 I4 --- HST !HST Program Number
35 A1 --- chip PC chip showing object
36- 44 A9 pix XY *Central coordinate of quasar
46- 49 A4 arcsec off Offset from designated position on chip 6
51- 54 A4 marcsec drift Drift rate (g = guided exposure)
55- 58 A4 mag V_obs Observed V (I indicates F785LP filter)
60- 64 F5.2 mag V_ver ?Magnitude tabulated by Veron
66 A1 --- disc *Discovery method
68- 71 F4.2 km/sec redsh [1.01/3.41]?Redshift
73- 76 F4.1 mag M ?Absolute magnitude
78- 81 A4 --- note *Notes
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Note on name:
blank indicates repeated observation of preceding quasar
Note on XY:
The coordinate of the center of the mosaic (not the chip) is 1, 1
Note on disc:
R = radio selected
C = selected by color
S = Emission lines in spectrum
O = Other (e.g. variability)
Note on note:
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.
References:
Bahcall, J.N., Maoz, D., Doxsey, R., Schneider, D.P., Bahcall, N.A., Lahav,
O. Yanny, B. 1992a, ApJ, 387, 56 (Paper I)
Bahcall, J.N., Maoz, D., Schneider, D.P., Yanny, B., and Doxsey, R., 1992b,
ApJ, 392, L1
Bahcall, J.N., Hartig, G., Jannuzi, B.T., Maoz, D., & Schneider, D.P. 1992c,
ApJL, 400, in press
Gould, A., Bahcall, J.N., & Maoz, D. 1992, ApJS, 88, 5
Hunter, D., Faber, S., Light, R., & Shaya, E. 1992, in "WFPC Final
Orbital/Science Verification Report", ed. S.M. Faber (Baltimore: STScI)
ch. 12
Magain, P., Surdej, J., Vanderriest, C., Pirenne, B., and Hutsemekers, D.
1992, AA, 253, L13
Maoz, D., Bahcall, J.N., Schneider, D.P., Doxsey, R., Bahcall, N.A.,
Filippenko, A.V., Goss, W.M., Lahav, O. & Yanny, B. 1992a, ApJL, 386, L1
Maoz, D., Bahcall, J.N., Schneider, D.P., Doxsey, R., Bahcall, N.A., Lahav,
O. & Yanny, B. 1992b, ApJ, 394, 51 (Paper II)
Maoz, D., Bahcall, J.N., Schneider, D.P., Doxsey, R., Bahcall, N.A., Lahav,
O. & Yanny, B. 1993, ApJ, 402, 69 (Paper III)
Maoz, D., Bahcall, J.N., Schneider, D.P., Bahcall, N.A., Djorgovski, S.,
Gould, A., Kirhakos, S., Doxsey, R., Meylan, G., & Yanny, B. 1993, ApJ,
409, 28 (Paper IV)
Schneider, D.P., et al. 1992, PASP, 104, 678
Veron-Cetty, M.P., & Veron, P. 1987, "A Catalogue of Quasars and Active
Nuclei (3rd Edition)" (Munich:ESO)
Veron-Cetty, M.P., & Veron, P. 1989, "A Catalogue of Quasars and Active
Nuclei (4th Edition)" (Munich:ESO)
Veron-Cetty, M.P., & Veron, P. 1991, "A Catalogue of Quasars and Active
Nuclei (5th Edition)" (Munich:ESO)
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(End) D. Maoz and N.G. Roman [Inst. Adv. Studies, NSSDC/ADC] 4-Aug-1994