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CLASS B0739+366, a double image gravitational lens

Lens System Summary

This double-image lens has significantly extended, weak VLBA substructure. NICMOS shows the two images and the lensing galaxy. Predictions from modelling suggest that the time delay between the images is too small to be effectively monitored (7 h-1 days). This lens is not in the CLASS complete sample because it is too faint at 5GHz.

This Lens System

Lens name B0739+366
Survey CLASS
Images 2
B1950.0 coords 07h39m32.507s 36°41'51.880"
J2000.0 coords 07h42m51.169s 36°34'43.638"

Lens System Structure and Labelling

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

Images labelled as in Marlow et al.

Image/Lens Positions

Image/Lens Relative Position
East (mas) North (mas)
A1 +0.0 +0.0
A2 +2.4 +1.0
B +221.7±1 -491.0±1

Image/Lens Separations

Separation (mas)
Component A1 A2 B
2.6 538.7
A2 2.6
B 538.7 538.7
Position angle (°)
Component A1 A2 B
-112.6 -24.3
A2 67.4
B 155.7 156.0

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.

MERLIN maps Click to see a larger version
MERLIN 5GHz image
VLBA maps Click to see a larger version
VLBA 1.7GHz image, component A
Click to see a larger version
VLBA 1.7GHz image, component B

Radio Flux Densities

Component Flux density (mJy)
1.7 GHz 5 GHz 5 GHz 5 GHz 5 GHz 8.4 GHz 8.4 GHz 15 GHz
A Detected
6.9X Detected 26.8 21.7 20.3 19.1
A1 " 29.0

A2 " 2.1

B " 6.2 X " 4.9 3.4 3.8 2.8
Flux errors

10% 10% 10% 10%
Resolution (mas) 7.7x5.4 3.8x1.5 50 50 200 200 200 200
Map noise level
0.045 0.11

Date observed 1999/08/29 1997/08/07 1996/12/27 1998/12/4 1999/08/30 1995/08/13 1999/08/30 1999/08/30
Reference [1] [1] [1] [1] [1] [1] [1] [1]

Sub-millimetre Flux Densities

Component Flux density (mJy)
1300 μm 850 μm 450 μm
Total <2.8 6.6±1.3 36±8
cal. error

5-10% 5-10%
Instrument IRAM 30-m SCUBA (JCMT) SCUBA (JCMT)
Date observed
1999-2001 1999-2001
Reference [2] [2] [2]

Optical Imaging

Component Brightness (Magnitudes)
F160W (H)
A 19.0
B 21.7
Lensing galaxy 21.7
Instrument NICMOS (HST)
Integration time
PSF size (arcsec)
Pixel scale (mas/pixel) 43
Date observed 1998/04/10
Reference no. [1]

Lens Models

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

Marlow et al. fixed SIE to point of peak surface brightness in NICMOS image. Constraints from VLBA unused since substructure is weak and heavily resolved. Suggests time delay between images A and B of 7 h-1 days, i.e. probably too short for effective monitoring.


  1. VLBA substructure consists of very weak and significantly extended jets. Difficult to constrain mass models using these.

  2. No redshifts available for this system as yet.

  3. It's likely that the time delay is too short to be properly monitored.


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] CLASS B0739+366: A new two-image gravitational lens system, D. R. Marlow et al., Astron. J. vol. 121, p. 619 (2001)

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

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