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).
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This Lens System
Lens name
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B1938+666
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Survey
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JVAS
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Images
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4
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B1950.0 coords
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19h38m12.944s
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66°41'56.110"
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J2000.0 coords
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19h38m25.290s
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66°48'52.960"
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Lens System Structure and Labelling
Image labelling for this lens (RA increases to the left, declination increases upwards)
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Image/Lens Positions
Image/Lens
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Relative Position
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East (mas)
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North (mas)
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A1
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+0.0
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+0.0
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A2
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-98
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+77
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B1
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-53
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+860
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B2
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-310
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+973
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C1a
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-581
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+695
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C1b
|
-598
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+667
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C2a
|
-664
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+526
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C2b
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-648
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+574
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Image/Lens Separations
Separation (mas)
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Component
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A1
|
A2
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B1
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B2
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C1a
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C1b
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C2a
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C2b
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A1
|
|
124.6
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861.6
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1021.2
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905.9
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895.8
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847.1
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865.7
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A2
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124.6
|
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784.3
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920.7
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784.4
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773.4
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722.5
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741.3
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B1
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861.6
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784.3
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280.7
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553.2
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578.2
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696.3
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660.2
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B2
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1021.2
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920.7
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280.7
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388.2
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420.2
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570.2
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522.9
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C1a
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905.9
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784.4
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553.2
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388.2
|
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32.8
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188.3
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138.3
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C1b
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895.8
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773.4
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578.2
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420.2
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32.8
|
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155.7
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105.6
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C2a
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847.1
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722.5
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696.3
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570.2
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188.3
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155.7
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50.6
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C2b
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865.7
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741.3
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660.2
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522.9
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138.3
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105.6
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50.6
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Position angle (°)
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Component
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A1
|
A2
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B1
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B2
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C1a
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C1b
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C2a
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C2b
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A1
|
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128.2
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176.5
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162.3
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140.1
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138.1
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128.4
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131.5
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A2
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-51.8
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-176.7
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166.7
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142.0
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139.7
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128.4
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132.1
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B1
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-3.5
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3.3
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113.7
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72.6
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70.5
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61.3
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64.3
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B2
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-17.7
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-13.3
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-66.3
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44.3
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43.3
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38.4
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40.3
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C1a
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-39.9
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-38.0
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-107.4
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-135.7
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31.3
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26.2
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29.0
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C1b
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-41.9
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-40.3
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-109.5
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-136.7
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-148.7
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25.1
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28.3
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C2a
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-51.6
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-51.6
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-118.7
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-141.6
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-153.8
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-154.9
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-161.6
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C2b
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-48.5
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-47.9
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-115.7
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-139.7
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-151.0
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-151.7
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18.4
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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.
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Radio Flux Densities
Component
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Flux density (mJy)
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1.612 GHz
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1.658 GHz
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5 GHz
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8.4 GHz
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15 GHz
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22 GHz
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A
|
25.7
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|
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12.6
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5.9
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2.7
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A1
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5.4
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11.9
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|
|
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A2
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3.4
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4.2
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|
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B
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|
|
|
|
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17
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B1
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63.7
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18.9
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32.6
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38.6
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18.9
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B2
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30.1
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7.9
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10.5
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4.2
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4.3
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B3
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|
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2.7
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|
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C
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|
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170.7
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62.7
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27.3
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C1
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155.9
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48.9
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|
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C1a
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43.5
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|
|
|
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C1b
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20.9
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C2
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142.0
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22.1
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47.9
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Flux errors
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|
|
|
|
|
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Resolution (mas)
|
100
|
5
|
40
|
200
|
160
|
100
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Map noise level (mJy/beam)
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0.1
|
0.12
|
0.17
|
0.27
|
0.28
|
0.57
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Instrument
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MERLIN
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VLBI
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MERLIN
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VLA
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VLA
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VLA
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Date observed
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1993/04
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1992/06
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1992/06
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1990/02
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1994/09
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1994/03
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Reference
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[3]
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[3]
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[3]
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[1]
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[3]
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[3]
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Sub-millimetre Flux Densities
Component
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Flux density (mJy)
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1300 μm
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850 μm
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450 μm
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Total
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14.7±2.0
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34.6±2.0
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126±22
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Estimated cal. error
|
|
5-10%
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5-10%
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Instrument
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SCUBA (JCMT)
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SCUBA (JCMT)
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SCUBA (JCMT)
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Date observed
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|
1999-2001
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1999-2001
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Reference
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[8]
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[8]
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[8]
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Optical Imaging
Component
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Brightness (Magnitudes)
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F160W
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H
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J
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K'
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g
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r
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Source
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21.5
|
|
|
|
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Lensing galaxy
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18.6±0.3
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|
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Total
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18.0±0.3
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17.6±0.1
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19.7±0.13
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17.1±0.1
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23.9±0.22
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>24.3(95%)
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Instrument
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NIC1/NICMOS (HST)
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GRIM II (APO)
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GRIM II (APO)
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GRIM II (APO)
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DIS (APO)
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DIS (APO)
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Integration time
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3hr 16 sec in 4ex
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48ex @ 25 sec
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29ex @ 25 sec
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82ex @ 9 sec
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48 min
|
48 min
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PSF size (arcsec)
|
0.14
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1.6-1.8
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1.6-1.8
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1.6-1.8
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1.6-1.8
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1.6-1.8
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Pixel scale (mas/pixel)
|
43
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|
|
|
|
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Date observed
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1997/09/13
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1995/07/02
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1995/08/06
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1995/08/06
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1995/07
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1995/08/05
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Reference no.
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[4]
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[2]
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[2]
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[2]
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[2]
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[2]
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Radio Image Polarisations
Image
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Radio Polarisation(%)
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Polarisation angle(°)
|
1.612 GHz
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5 GHz
|
15 GHz
|
1.612 GHz
|
5 GHz
|
15 GHz
|
A1
|
|
8
|
|
|
|
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B1
|
|
6
|
6
|
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69.2
|
-23
|
C1
|
1.4
|
14.3
|
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-57
|
63
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-12
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C2
|
1.4
|
15.3
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|
58
|
74
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-12
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C
|
|
|
15
|
|
|
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Resolution (mas)
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100
|
40
|
160
|
100
|
40
|
160
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Map noise level
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0.1
|
0.17
|
0.28
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0.1
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0.17
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0.28
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Instrument
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MERLIN
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MERLIN
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VLA
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MERLIN
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MERLIN
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VLA
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Date observed
|
1993/04
|
1992/06
|
1994/09
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1993/04
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1992/06
|
1994/09
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Reference no.
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[3]
|
[3]
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[3]
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[3]
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[3]
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[3]
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Redshifts
Object
|
Redshift
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Instrument
|
Date Observed
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Reference
|
Lens galaxy
|
0.878
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LRIS (Keck II)
|
1998/07/23
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[6]
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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.
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Notes
Complete Einstein ring seen in IR; significant arc in radio
Not part of the statistically complete JVAS/CLASS sample; precluded by extended emission and spectral index of about 0.5.
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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.
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[1] Interferometer Phase Calibration Sources (1), A. R. Patnaik et al., Mon. Not. R. Astron. Soc. 254, pp. 655-676 (1992)
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[2] Infrared Counterpart of the Gravitational Lens 1938+66.6, J. E. Rhoads et al., Astron. J. 111, p. 642 (1996)
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[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)
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[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)
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[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)
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[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)
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[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)
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[8] A submillimeter survey of gravitationally lensed quasars, R. Barvainis and R. Ivison, Astrophys. J. 571, pp. 712-720 (2002)
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