CASSOWARY

CASSOWARY Gravitational Lenses
 
C A S S O W A R Y
Cambridge And Sloan Survey OWide ARcs in the skY
The Cassowary is the second largest flightless bird on the planet. 

Artist impression of the Cosmic Horseshoe lens by Brendon Brewer
 
The Survey
The aim is to carry out systematic searches for wide separation (>1.5 arcsec) gravitational lens systems, looking for multiple, blue companions around massive ellipticals in the Sloan Digital Sky Survey (SDSS) object catalogue. Typically, the target systems correspond to lensing of z > 0.5 star-forming galaxies by luminous red galaxies and brightest cluster galaxies. The survey started in the summer of 2007 and the first version of the catalogue was published in June 2008.
 
The Catalogue
The current version (08th June, 2011 ) of the CASSOWARY catalogue contains 45 objects (counting binaries twice).
It is also available for download as an ASCII table. The 14 collumns are: CSWA ID, SDSS ObjID, RA (deg), Dec (deg), SDSS lens magnitudes (not corrected for Galactic extinction) u, g, r, i, z, SDSS SpecObj ID, lens redshift, redshift reference, source redshift, redshift reference. Missing values are indicated by -99.
 
The ObjIDs of the arc knots (as resolved by the SDSS pipeline) are also available. These are used to generate arc total magnitudes.
Note RADec is linked to SDSS's Navigate page, ObjID to Explore page, SpecObj to object's spectrum GIF
View according to  
CSWA 1 a.k.a. Cosmic Horseshoe
ObjId 587742572151374147
RADec 177.1380745  19.50087261
ugriz L 23.3 20.8 19.0 18.2 17.8
ugriz S 20.2 19.8 19.5 19.5 18.7
No SDSS spectrum
ZL 0.4441  ZS 2.3791
CSWA 2.1 a.k.a. Cheshire Cat
ObjId 588013382200131773
RADec 159.68160026  48.8215933
ugriz L 23.0 20.3 18.6 17.9 17.4
ugriz S 21.2 20.4 20.1 19.9 19.3
SpecObj 246515463746486272
ZL 0.4260  ZS 0.972
CSWA 2.2 a.k.a. Cheshire Cat
ObjId 588013382200131774
RADec 159.67786606  48.82229409
ugriz L 22.3 20.6 18.8 18.2 17.7
ugriz S 21.2 20.4 20.1 19.9 19.3
No SDSS spectrum
ZL 0.4322  ZS 0.972
CSWA 3
ObjId 588017605222793376
RADec 190.1345157  45.15079076
ugriz L 21.2 20.0 18.4 17.9 17.6
ugriz S 19.8 19.6 19.7 19.4 19.4
No SDSS spectrum
ZL 0.2742  ZS 0.7252
CSWA 4 a.k.a. SDSS J090122.37+181432.3
ObjId 588023046402670876
RADec 135.34321049  18.24231627
ugriz L 21.5 19.7 18.0 17.3 17.0
ugriz S 22.5 21.4 21.2 20.8 19.7
SpecObj 642838136396709888
ZL 0.3460  ZS 2.25867
CSWA 5.1
ObjId 588848901528223970
RADec 191.21400615  1.11193257
ugriz L 22.3 20.6 19.1 18.4 18.0
ugriz S 20.5 20.6 20.7 20.6 20.2
No SDSS spectrum
ZL ?  ZS 1.068615
CSWA 5.2
ObjId 588848901528223971
RADec 191.21257821  1.11222194
ugriz L 22.3 20.4 18.4 17.9 17.7
ugriz S 20.5 20.6 20.7 20.6 20.2
SpecObj 82132249671106560
ZL 0.3880  ZS 1.068615
CSWA 6 a.k.a. The Clone
ObjId 588013382206357664
RADec 181.50871224  51.70820438
ugriz L 22.7 20.0 18.4 17.7 17.3
ugriz S 21.2 20.0 19.7 19.4 19.1
SpecObj 248767590678134784
ZL 0.4330  ZS 2.008
CSWA 7 a.k.a. SDSS J1137 + 4936
ObjId 588295841784725744
RADec 174.41690253  49.60987175
ugriz L 24.5 21.2 19.4 18.6 18.2
ugriz S 20.6 20.3 20.3 20.1 20.0
SpecObj 272412374034546688
ZL 0.4480  ZS 1.4116
CSWA 8 a.k.a. SDSS J120923.7+264047
ObjId 587741600957333763
RADec 182.34869727  26.6796452
ugriz L 24.9 20.8 19.0 17.9 17.4
ugriz S 21.5 21.8 21.3 20.4 19.8
SpecObj 627638892169789440
ZL 0.5580  ZS 1.0185
CSWA 9
ObjId 587742902862086260
RADec 186.82808228  17.43107014
ugriz L 22.7 19.9 17.9 17.3 16.8
ugriz S 22.2 21.4 21.1 20.8 19.2
No SDSS spectrum
ZL 0.37-1  ZS ?
CSWA 10
ObjId 587730773880078847
RADec 339.63047433  13.33218384
ugriz L 21.3 19.8 17.9 17.2 16.7
ugriz S 21.2 20.7 20.1 19.9 19.2
SpecObj 208235580448833536
ZL 0.4130  ZS 1.018
CSWA 11
ObjId 587744873710682762
RADec 120.05441848  8.20232396
ugriz L 22.4 19.3 17.7 17.0 16.7
ugriz S 20.3 19.9 19.9 20.0 19.4
No SDSS spectrum
ZL 0.31-1  ZS ?
CSWA 12 a.k.a. MACS J1133.2+5008
ObjId 587732484357095512
RADec 173.30488333  50.14447842
ugriz L 20.7 19.4 18.1 17.5 17.0
ugriz S 21.6 21.6 21.0 20.5 20.9
No SDSS spectrum
ZL 0.3944  ZS 1.5444
CSWA 13
ObjId 587731870173298881
RADec 189.40082835  55.56190979
ugriz L 23.4 20.7 18.8 18.1 17.5
ugriz S 19.9 19.7 19.8 19.6 19.5
SpecObj 287330913719681024
ZL 0.4100  ZS ?
CSWA 14
ObjId 587736980648362708
RADec 260.90067032  34.19946453
ugriz L 22.6 20.1 18.4 17.6 17.3
ugriz S 20.6 20.3 20.4 20.6 19.2
No SDSS spectrum
ZL 0.44418  ZS 0.99518
CSWA 15.1
ObjId 587742014344265970
RADec 152.2490633  19.62151556
ugriz L 21.3 19.0 17.4 16.7 16.5
ugriz S 23.3 22.0 22.0 22.5 20.6
SpecObj 667889578840948736
ZL 0.3060  ZS ?
CSWA 15.2
ObjId 587742014344265969
RADec 152.24695521  19.62092953
ugriz L 21.8 19.3 17.6 16.8 16.4
ugriz S 23.3 22.0 22.0 22.5 20.6
SpecObj 668171053188513792
ZL 0.4650  ZS ?
CSWA 16.1
ObjId 587731868557115670
RADec 167.76534454  53.14858718
ugriz L 22.1 20.2 18.7 18.0 17.6
ugriz S 21.8 20.7 20.7 20.5 19.8
No SDSS spectrum
ZL 0.33-1  ZS ?
CSWA 16.2
ObjId 587731868557115671
RADec 167.76378766  53.14774276
ugriz L 24.5 20.7 19.0 18.2 17.8
ugriz S 21.8 20.7 20.7 20.5 19.8
No SDSS spectrum
ZL 0.46-1  ZS ?
CSWA 17
ObjId 587741709956546742
RADec 174.53730655  27.9085314
ugriz L 21.6 20.4 18.7 18.1 17.8
ugriz S 24.1 22.0 21.6 21.4 20.8
No SDSS spectrum
ZL 0.33-1  ZS ?
CSWA 18
ObjId 587742191511273514
RADec 173.52808224  25.55977002
ugriz L 17.3 15.3 14.4 14.0 13.7
ugriz S 20.3 19.4 19.3 19.1 18.9
SpecObj 587742191511273514
ZL 0.070  ZS ?
CSWA 19
ObjId 587741421640024462
RADec 135.01101894  22.56801561
ugriz L 24.1 21.1 19.1 18.2 17.9
ugriz S 20.3 19.9 19.8 19.8 19.3
SpecObj 643119522567421952
ZL 0.4890  ZS 2.032513
CSWA 20
ObjId 587742611340001632
RADec 220.4548069  14.68904854
ugriz L 24.6 25.1 22.7 20.7 20.2
ugriz S 20.1 20.1 19.9 19.9 19.7
No SDSS spectrum
ZL 0.7419  ZS 1.4339
CSWA 21 a.k.a. 8 O'Clock Arc
ObjId 588290880028999911
RADec 5.67049154  14.51956525
ugriz L 22.1 20.1 18.4 17.8 17.3
ugriz S 23.0 20.0 19.8 19.7 19.5
SpecObj 212174997320368128
ZL 0.3810  ZS 2.7310
CSWA 22 a.k.a. Hall's Arc
ObjId 587727230523080836
RADec 26.73337065  -9.49791496
ugriz L 21.6 20.3 18.5 17.8 17.6
ugriz S 21.0 20.4 19.9 19.2 19.5
SpecObj 187123470625144832
ZL 0.4411  ZS 1.94418
CSWA 23 a.k.a. SDSS J082728.70+223256.4
ObjId 587739115775197598
RADec 126.87013375  22.54831707
ugriz L 24.9 20.5 18.8 18.2 17.8
ugriz S 20.0 19.9 20.2 19.4 19.2
No SDSS spectrum
ZL 0.34912  ZS 0.76612
CSWA 24 a.k.a. SDSS J151118.73+471340.3
ObjId 587733412060987606
RADec 227.82806483  47.22787249
ugriz L 24.4 20.1 18.4 17.6 17.1
ugriz S 22.9 22.3 23.1 22.2 22.2
SpecObj 295775162215694336
ZL 0.4526  ZS 0.986
CSWA 25 a.k.a. SDSS J104943.14+442035.6
ObjId 588297863115047025
RADec 162.42975402  44.34322791
ugriz L 21.3 18.6 17.0 16.5 16.2
ugriz S 21.4 20.8 20.3 19.9 19.4
SpecObj 403862977867939840
ZL 0.2306  ZS 0.46
CSWA 26 a.k.a. SDSS J111310.64+235639.5
ObjId 587741829121638526
RADec 168.294359  23.94431091
ugriz L 21.0 18.2 16.5 15.8 15.5
ugriz S 23.7 21.7 20.8 20.6 19.9
SpecObj 701949540034412544
ZL 0.3366  ZS 0.776
CSWA 27 a.k.a. SDSS J162954.56+352839.4
ObjId 587733441053065699
RADec 247.47734696  35.47763614
ugriz L 20.1 18.2 16.9 16.4 16.0
ugriz S 19.3 19.8 19.1 18.8 18.7
No SDSS spectrum
ZL 0.176  ZS 0.856
CSWA 28 a.k.a. SDSS J134332.85+415503.4
ObjId 588017625088393410
RADec 205.88688803  41.91763425
ugriz L 23.3 20.2 18.3 17.6 17.2
ugriz S 21.2 20.8 20.4 20.1 19.6
SpecObj 378810679156539392
ZL 0.41813  ZS 2.09313
CSWA 29
ObjId 587745403607319063
RADec 130.08769754  10.8701825
ugriz L 21.4 19.9 18.4 17.9 17.6
ugriz S 21.8 21.3 21.4 21.5 20.8
No SDSS spectrum
ZL 0.22-1  ZS ?
CSWA 30
ObjId 587732483269198209
RADec 132.8604223  35.97049854
ugriz L 21.1 18.7 17.1 16.6 16.2
ugriz S 22.8 22.9 23.4 24.1 21.1
SpecObj 263123855206252544
ZL 0.2720  ZS 0.91918
CSWA 31
ObjId 588023239671939597
RADec 140.3572627  18.17148017
ugriz L 27.4 22.1 19.8 18.4 17.9
ugriz S 20.6 20.3 19.7 19.8 18.6
SpecObj 686748518408257536
ZL 0.6830  ZS ?
CSWA 32
ObjId 587729386608722049
RADec 153.77402666  55.50505929
ugriz L 20.7 18.7 17.4 16.9 16.5
ugriz S 20.5 20.1 19.6 19.5 18.9
No SDSS spectrum
ZL 0.20518  ZS 0.27618
CSWA 33
ObjId 587738617559843056
RADec 162.34745045  35.74471377
ugriz L 21.0 19.4 17.8 17.1 16.8
ugriz S 23.2 23.2 22.3 20.7 19.4
SpecObj 588512323841294336
ZL 0.3220  ZS 1.02818
CSWA 34
ObjId 587727226228834771
RADec 4.25642966  -10.15308799
ugriz L 24.9 22.5 20.6 19.7 19.3
ugriz S 22.0 21.1 20.5 20.1 20.1
No SDSS spectrum
ZL 0.5-1  ZS ?
CSWA 35 a.k.a. SDSS J095739.1+05093
ObjId 587732701250519458
RADec 149.41329988  5.15886783
ugriz L 21.3 20.5 18.9 18.1 17.6
ugriz S 21.3 20.5 20.0 19.7 19.6
No SDSS spectrum
ZL 0.44-1  ZS 1.82319
CSWA 36 a.k.a. maxBCG J120735.9+525459
ObjId 588013383817101501
RADec 181.89964171  52.91645343
ugriz L 21.9 19.0 17.5 16.9 16.7
ugriz S 22.5 20.8 20.4 19.9 19.4
No SDSS spectrum
ZL 0.27-1  ZS 1.925719
CSWA 37 a.k.a. SDSS J131811.5+394226
ObjId 588017979434795493
RADec 199.54796061  39.70748791
ugriz L 21.7 20.5 18.8 18.0 17.5
ugriz S 26.3 21.0 20.6 20.2 21.0
SpecObj 556705703943733248
ZL 0.4750  ZS 2.943719
CSWA 38 a.k.a. NSCS J122648.0+215157
ObjId 587742013284679929
RADec 186.71535583  21.87373676
ugriz L 22.6 20.8 19.1 18.4 17.9
ugriz S 25.1 20.4 19.9 19.8 19.8
No SDSS spectrum
ZL 0.42-1  ZS 2.923317
CSWA 39 a.k.a. SGAS J122651.3+215220
ObjId 587736542562419006
RADec 231.93759592  6.87607048
ugriz L 23.4 20.7 18.9 18.2 17.7
ugriz S 24.8 20.9 20.7 20.9 21.1
SpecObj 512237232292102144
ZL 0.3916  ZS 2.759317
CSWA 40 a.k.a. SDSS J0952+3434
ObjId 587738948281499819
RADec 148.16760451  34.5794650
ugriz L 24.3 20.6 18.9 18.2 17.8
ugriz S 22.7 21.5 21.1 21.0 20.5
No SDSS spectrum
ZL 0.34919  ZS 2.189619
CSWA 41 a.k.a. SDSS J1450+3908
ObjId 588017605770477796
RADec 222.62769859  39.1386469
ugriz L 21.1 19.1 17.6 17.0 16.7
ugriz S 21.3 21.5 22.0 22.1 22.5
SpecObj 380217935211266048
ZL 0.2890  ZS 0.861319
The Follow-up
We have obtained follow-up for some of these systems on a number of telescopes including
However, most of the candidates still require spectroscopic confirmation and/or deeper imaging. We welcome the community worldwide to join on the effort of studying these spectacular systems.
 

References
-1. SDSS photometric redshift, -99, -99
0. SDSS spectroscopic redshift, -99, -99
1. "The Cosmic Horseshoe: Discovery of an Einstein Ring around a Giant Luminous Red Galaxy", Belokurov et al., 2007
2. "Models of the Cosmic Horseshoe Gravitational Lens", Dye et al., 2008
3. "Two New Large Separation Gravitational Lenses from SDSS", Belokurov et al., 2008
4. "A Systematic Search for Gravitationally Lensed Arcs in the Hubble Space Telescope WFPC2 Archive", Sand et al., 2005
5. "SDSS J120923.7+264047: A new massive galaxy cluster with a bright giant arc", Ofek et al., 2008
6. "The Sloan Bright Arcs Survey: Six Strongly Lensed Galaxies at z = 0.4-1.4", Kubo et al., 2009
7. "Rest-Frame Optical Spectra of Three Strongly Lensed Galaxies at z~2", Hainline et al., 2009
8. "Discovery of A Very Bright Strongly-Lensed z=2 Galaxy in the SDSS DR5", Lin et al., 2008
9. "CASSOWARY 20: a Wide Separation Einstein Cross Identified with the X-shooter Spectrograph", Pettini et al., 2009
10. "The 8 O'Clock Arc: A Serendipitous Discovery of a Strongly Lensed Lyman Break Galaxy", Allam et al., 2007
11. "A Systematic Search for High Surface Brightness Giant Arcs in a Sloan Digital Sky Survey Cluster Sample", Estrada et al., 2007
12. "The Sloan Digital Sky Survey Discovery of a Strongly Lensed Post-Starburst Galaxy at z = 0.766", Shin et al., 2008
13. "The Sloan Bright Arcs Survey: Four Strongly Lensed Galaxies with Redshift > 2", Diehl et al., 2009
14. "Discovery of four gravitational lensing systems by clusters in the SDSS DR6", Wen et al., 2009
15. "X-shooter observations of the gravitational lens system CASSOWARY 5", Christensen et al., 2010
16. "A New Survey for Giant Arcs", Hennawi et al., 2008
17. "Two Lensed z~3 Lyman Break Galaxies Discovered in the SDSS Giant Arcs Survey", Koester et al., 2010
18. "CASSOWARY Data Release 1", -99, -99
19. "The Sloan Bright Arcs Survey: Discovery of Seven New Strongly Lensed Galaxies from z = 0.66-2.94", Kubo et al., 2011
 

The People
@IoA: Vasily Belokurov, Wyn Evans, Paul Hewett, Lindsay King, Richard McMahon, Lukasz Wyrzykowski, Max Pettini, Martin Smith, Mike Irwin
@SAO: Alexei Moiseev
@Sydney: Geraint Lewis
@UCSB: Brendon Brewer
@MPIA: Sergey Koposov
@Nottingham: Simon Dye
@Imperial: Stephen Warren
 

Credits
The catalogue is distributed freely. The candidate selection procedure is described in our latest paper.

As most of the information presented here is based on the SDSS data, one might want to consider using standard SDSS acknowledgement as well.