J/AJ/132/999 SDSS quasar lens search (Oguri+, 2006)
The Sloan Digital Sky Survey quasar lens search.
I. Candidate selection algorithm.
Oguri M., Inada N., Pindor B., Strauss M.A., Richards G.T., Hennawi J.F.,
Turner E.L., Lupton R.H., Schneider D.P., Fukugita M., Brinkmann J.
<Astron. J., 132, 999-1013 (2006)>
=2006AJ....132..999O 2006AJ....132..999O
ADC_Keywords: QSOs ; Gravitational lensing
Keywords: gravitational lensing - quasars: general
Abstract:
We present an algorithm for selecting a uniform sample of
gravitationally lensed quasar candidates from low-redshift (0.6<z<2.2)
quasars brighter than i=19.1 that have been spectroscopically
identified in the Sloan Digital Sky Survey (SDSS). Our algorithm uses
morphological and color selections that are intended to identify
small- and large-separation lenses, respectively. Our selection
algorithm only relies on parameters that the SDSS standard image
processing pipeline generates, allowing easy and fast selection of
lens candidates. The algorithm has been tested against simulated SDSS
images, which adopt distributions of field and quasar parameters taken
from the real SDSS data as input. Furthermore, we take differential
reddening into account. We find that our selection algorithm is almost
complete down to separations of 1" and flux ratios of 10-0.5.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 33 525 Completeness for double lenses
table2.dat 101 20 Quadruply lensed quasars used in the simulation
table3.dat 41 525 Completeness for quadruple lenses
--------------------------------------------------------------------------------
See also:
J/A+A/340/371 : Quasar polarization (Hutsemekers+ 1998)
J/ApJ/409/28 : Gravitationally Lensed Quasars (Maoz + 1993)
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.2 [-] log(Fratio) Log (base 10) of the flux ratio
7- 9 F3.1 arcsec Sep Image Separation
11- 15 F5.3 --- Ctot ]0/1[ Total Completeness
17- 21 F5.3 --- Cmor ]0/1[ Completeness for morphological selection
23- 27 F5.3 --- Ccol [0/1[ Completeness for color selection
29- 33 F5.3 --- Cboth [0/0.3[ The fraction of lenses selected from
both morphological and color selections
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Name of the quadruple lenses
15- 19 A5 --- Type Type, based on visual inspection
21- 25 F5.2 arcsec Sep Maximum separation between multiple images
27- 30 F4.2 --- fquad Flux ratio between the brightest image and the
image farthest from the brightest image
32- 69 A38 --- Ref Reference (1)
71-101 A31 --- SName Simbad name
--------------------------------------------------------------------------------
Note (1): The reference from which we adopt the image positions and fluxes
for the simulation. For fluxes, we use those of the i-band (F814W for
the Hubble Space Telescope data) image when the optical data are
available. If not, we adopt those of the radio-band image. CASTLES
corresponds to C. S. Kochanek et al., CASTLES survey,
http://cfa-www.harvard.edu/castles/
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Name of quadruple lenses
15- 17 F3.1 arcsec Sep Image Separation
19- 23 F5.3 --- Ctot ]0/1[ Total Completeness
25- 29 F5.3 --- Cmor ]0/1[ Completeness for morphological selection
31- 35 F5.3 --- Ccol [0/1[ Completeness for color selection
37- 41 F5.3 --- Cboth [0/1[ The fraction of lenses selected from
both morphological and color selections
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 25-Apr-2008