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JVAS B1938+666, a quad image gravitational lens



Lens System Summary

B1938+666 is a quad-image lens, and was discovered in JVAS. HST observations show an Einstein ring in IR, and in radio there is a significant arc visible. Much of the radio emission is extended and has a spectral index of about 0.5. Therefore the system is excluded from the JVAS/CLASS statistically complete sample. The lens redshift is 0.878, but the source redshift is not yet known (IR spectroscopy required).

This Lens System

Lens name B1938+666
Survey JVAS
Images 4
B1950.0 coords 19h38m12.944s 66°41'56.110"
J2000.0 coords 19h38m25.290s 66°48'52.960"

Lens System Structure and Labelling

Image labelling for this lens (RA increases to the left, declination increases upwards)

Components labelled as in King et al.

Image/Lens Positions

Image/Lens Relative Position
East (mas) North (mas)
A1 +0.0 +0.0
A2 -98 +77
B1 -53 +860
B2 -310 +973
C1a -581 +695
C1b -598 +667
C2a -664 +526
C2b -648 +574

Image/Lens Separations

Separation (mas)
Component A1 A2 B1 B2 C1a C1b C2a C2b
A1
124.6 861.6 1021.2 905.9 895.8 847.1 865.7
A2 124.6
784.3 920.7 784.4 773.4 722.5 741.3
B1 861.6 784.3
280.7 553.2 578.2 696.3 660.2
B2 1021.2 920.7 280.7
388.2 420.2 570.2 522.9
C1a 905.9 784.4 553.2 388.2
32.8 188.3 138.3
C1b 895.8 773.4 578.2 420.2 32.8
155.7 105.6
C2a 847.1 722.5 696.3 570.2 188.3 155.7
50.6
C2b 865.7 741.3 660.2 522.9 138.3 105.6 50.6
Position angle (°)
Component A1 A2 B1 B2 C1a C1b C2a C2b
A1
128.2 176.5 162.3 140.1 138.1 128.4 131.5
A2 -51.8
-176.7 166.7 142.0 139.7 128.4 132.1
B1 -3.5 3.3
113.7 72.6 70.5 61.3 64.3
B2 -17.7 -13.3 -66.3
44.3 43.3 38.4 40.3
C1a -39.9 -38.0 -107.4 -135.7
31.3 26.2 29.0
C1b -41.9 -40.3 -109.5 -136.7 -148.7
25.1 28.3
C2a -51.6 -51.6 -118.7 -141.6 -153.8 -154.9
-161.6
C2b -48.5 -47.9 -115.7 -139.7 -151.0 -151.7 18.4

Maps and Images

Click on an image to see a larger JPEG version, or click on the accompanying text to download a gzipped FITS or PostScript file of the map or image. The images and maps are available in one gzipped file here. To see a DSS image of the region around this lens, click here - note that you will have to start the search manually by clicking on the 'Search' button.

IR images Click to see a larger version
NICMOS image (contours) + model (greyscale)
King et al. (1998)
Combined images Click to see a larger version
HST/MERLIN and HST colour image
King et al. (1998)
Click to see a larger version
Combined HST and MERLIN image
King et al. (1998)
1.6GHz to 5GHz Click to see a larger version
1.6GHz MERLIN image
King et al. (1997)
Click to see a larger version
18cm VLBI image
King et al. (1997)
Click to see a larger version
5GHz MERLIN image
King et al. (1997)
5GHz to 22GHz Click to see a larger version
5GHz MERLIN image
Click to see a larger version
15GHz VLA image
King et al. (1997)
Click to see a larger version
22GHz VLA image
King et al. (1997)
Optical spectra Click to see a larger version
Spectrum from WHT

Radio Flux Densities

Component Flux density (mJy)
1.612 GHz 1.658 GHz 5 GHz 8.4 GHz 15 GHz 22 GHz
A 25.7

12.6 5.9 2.7
A1
5.4 11.9


A2
3.4 4.2


B




17
B1 63.7 18.9 32.6 38.6 18.9
B2 30.1 7.9 10.5 4.2 4.3
B3

2.7


C


170.7 62.7 27.3
C1 155.9
48.9


C1a
43.5



C1b
20.9



C2 142.0 22.1 47.9


Flux errors





Resolution (mas) 100 5 40 200 160 100
Map noise level
(mJy/beam)
0.1 0.12 0.17 0.27 0.28 0.57
Instrument MERLIN VLBI MERLIN VLA VLA VLA
Date observed 1993/04 1992/06 1992/06 1990/02 1994/09 1994/03
Reference [3] [3] [3] [1] [3] [3]

Sub-millimetre Flux Densities

Component Flux density (mJy)
1300 μm 850 μm 450 μm
Total 14.7±2.0 34.6±2.0 126±22
Estimated
cal. error

5-10% 5-10%
Instrument SCUBA (JCMT) SCUBA (JCMT) SCUBA (JCMT)
Date observed
1999-2001 1999-2001
Reference [8] [8] [8]

Optical Imaging

Component Brightness (Magnitudes)
F160W H J K' g r
Source 21.5




Lensing galaxy 18.6±0.3




Total 18.0±0.3 17.6±0.1 19.7±0.13 17.1±0.1 23.9±0.22 >24.3(95%)
Instrument NIC1/NICMOS (HST) GRIM II (APO) GRIM II (APO) GRIM II (APO) DIS (APO) DIS (APO)
Integration time 3hr 16 sec in 4ex 48ex @ 25 sec 29ex @ 25 sec 82ex @ 9 sec 48 min 48 min
PSF size (arcsec) 0.14 1.6-1.8 1.6-1.8 1.6-1.8 1.6-1.8 1.6-1.8
Pixel scale (mas/pixel) 43




Date observed 1997/09/13 1995/07/02 1995/08/06 1995/08/06 1995/07 1995/08/05
Reference no. [4] [2] [2] [2] [2] [2]

Radio Image Polarisations

Image Radio Polarisation(%) Polarisation angle(°)
1.612 GHz 5 GHz 15 GHz 1.612 GHz 5 GHz 15 GHz
A1
8



B1
6 6
69.2 -23
C1 1.4 14.3
-57 63 -12
C2 1.4 15.3
58 74 -12
C

15


Resolution (mas) 100 40 160 100 40 160
Map noise level 0.1 0.17 0.28 0.1 0.17 0.28
Instrument MERLIN MERLIN VLA MERLIN MERLIN VLA
Date observed 1993/04 1992/06 1994/09 1993/04 1992/06 1994/09
Reference no. [3] [3] [3] [3] [3] [3]

Redshifts

Object Redshift Instrument Date Observed Reference
Lens galaxy 0.878 LRIS (Keck II) 1998/07/23 [6]

Lens Models

Click on the model's reference number to go to the relevant paper's abstract on ADS.


[3]
Model of lensing galaxy used was asymptotically isothermal elliptical potential well. Ellipticity was fixed at 0.07.

[4]
Observations consistent with simple GLENS (AIPS) model.

Notes

  1. Complete Einstein ring seen in IR; significant arc in radio

  2. Not part of the statistically complete JVAS/CLASS sample; precluded by extended emission and spectral index of about 0.5.

References

Click here to see the CASTLES data available for this object, or here to search for references on NED. You can go to a paper's abstract on ADS by clicking its reference number.


[1] Interferometer Phase Calibration Sources (1), A. R. Patnaik et al., Mon. Not. R. Astron. Soc. 254, pp. 655-676 (1992)


[2] Infrared Counterpart of the Gravitational Lens 1938+66.6, J. E. Rhoads et al., Astron. J. 111, p. 642 (1996)


[3] Multifrequency radio observations of the gravitational lens system 1938+666, L. J. King et al., Mon. Not. R. Astron. Soc. 289, Issue 2, pp. 450-456 (1997)


[4] A complete infrared Einstein ring in the gravitational lens system B1938+666, L. J. King et al., Mon. Not. R. Astron. Soc. 295, No. 2, p. L41 (1998)


[5] Gravitationally lensed radio sources in the Jodrell Bank-VLA Astrometric Survey, L. J. King et al., Mon. Not. R. Astron. Soc. 307, pp. 225-235 (1999)


[6] Redshifts of the Gravitational Lenses MG 1131+0456 and B1938+666, J. L. Tonry & C. S. Kochanek, Astron. J. 119, Issue 3, pp. 1078-1082 (2000)


[7] IRAM observations of JVAS/CLASS gravitational lenses, E. Xanthopoulos, F. Combes, T. Wiklind, Mon. Not. R. Astron. Soc. 325, Iss. 1, p. 273 (2001)


[8] A submillimeter survey of gravitationally lensed quasars, R. Barvainis and R. Ivison, Astrophys. J. 571, pp. 712-720 (2002)

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