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JVAS B0218+357, a double image gravitational lens



Lens System Summary

JVAS lens B0218+357 is a double-image lens with an Einstein ring and a maximum image separation of 335 milli-arcseconds (A. R. Patnaik et al.). This is the smallest separation known for a galactic-mass lens. Other interesting features include high radio polarisation (~10%), high faraday rotation, depolarisation of image A at frequencies of 15GHz and below and extensive frequency-dependent radio structure. It has some of the highest molecular and HI absorptions of any lens and also has (probably) high extinction of image A. It exhibits a radio time delay of 10.5±0.5 days (A. D. Biggs et al.), and is a good candidate for the measurement of H0. The received flux density exceeds 1.2Jy at 8.4GHz, making it one of the brightest lenses in the CLASS/JVAS sample.

This Lens System

Lens name B0218+357
Survey JVAS
Images 2
B1950.0 coords 02h18m04.129s 35°42'31.830"
J2000.0 coords 02h21m05.470s 35°56'13.723"

Lens System Structure and Labelling

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

Images labelled as in Patnaik et al. Images labelled as in Patnaik et al. Images labelled as in Patnaik et al.

Image/Lens Positions

Relative positions obtained from 15GHz VLBA observations (see Patnaik, Porcas and Browne 1995)

Image/Lens Relative Position
East (mas) North (mas)
A1 +0.0 +0.0
A2 +1.07 +0.86
B1 +309.2 +127.4
B2 +310.6 +127.4

Image/Lens Separations

Separation (mas)
Component A1 A2 B1 B2
A1
1.4 334.4 335.7
A2 1.4
333.1 334.4
B1 334.4 333.1
1.4
B2 335.7 334.4 1.4
Position angle (°)
Component A1 A2 B1 B2
A1
-128.8 -112.4 -112.3
A2 51.2
-112.3 -112.2
B1 67.6 67.7
-90.0
B2 67.7 67.8 90.0

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.

Discovery images Click to see a larger version
Discovery map, VLA 8.4GHz
I. Browne
Optical and IR images Click to see a larger version
V-band WFPC-2 image
Jackson et al.
Click to see a larger version
I-band WFPC-2 image
Jackson et al.
Click to see a larger version
H-band NICMOS image
Jackson et al.
Maps of the
Einsten ring
Click to see a larger version
Einstein ring at 340MHz, VLBA (50 mas)
P. N. Wilkinson
Click to see a larger version
Einstein ring at 1.7GHz, EVN (50 mas)
A. R. Patnaik
Click to see a larger version
Extended structure, 5GHz MERLIN/VLA
A. D. Biggs
Click to see a larger version
Lens images & jet, 5GHz VLA (350 mas)
A. D. Biggs
Click to see a larger version
Extended structure, 15GHz VLA
A. D. Biggs
Radio maps showing A+B Click to see a larger version
Components A+B, 1.4GHz VLBA (8 mas)
P. N. Wilkinson
Click to see a larger version
Components A+B, 1.7GHz VLBA (5 mas)
P. N. Wilkinson
Click to see a larger version
Components A+B, 1.7GHz VLBA (8 mas)
P. N. Wilkinson
Click to see a larger version
Components A+B, 2.3GHz VLBA (5 mas)
P. N. Wilkinson
Click to see a larger version
Components A+B, 5GHz VLBI (8 mas)
P. N. Wilkinson
Radio maps of image A Click to see a larger version
Component A, 15GHz VLBA (0.5 mas)
Patnaik et al.
Radio maps of image B Click to see a larger version
Component B, 15GHz VLBA (0.5 mas)
Patnaik et al.

Radio Flux Densities

Component Flux density (mJy)
1.465 GHz 1.63 GHz 1.7 GHz 4.84 GHz 5 GHz 5 GHz 5 GHz 8.4 GHz 8.4 GHz 8.4 GHz 8.4 GHz 15 GHz 15 GHz 15.3 GHz 22 GHz 22 GHz 22.4 GHz 43 GHz
Total ~770 mJy/beam
(peak)

















Ring


133±13 236

158±16 186

126

101
167±40
A

445 880±80 728 660 515 807±40 767

698

654
833±160
A1




410


554±25 472
450 621±7
328
270
A2




250


223±5 218
121 379±5
100
75
B

170 370±20 245 210 196 271±15 236

189

180
253±50
B1








171±5 139
295 172±3
140
60
B2








59.9±3 63
66 104±3
41
22
Extended
structure

≥120















Flux errors

















Resolution (mas) 4900
5
50 5 1
200 1.3 1 120 0.5 0.5
0.3
0.2
Map noise level
(mJy/beam)













0.6



Instrument VLA VLA
A + C arrays
VLBI (mk3) VLA MERLIN EVN VLBI
VLA VLBI VLBI VLA VLBI VLBA VLA VLBI VLA VLBI
Date observed 1991/11/16 1990/02/09 (A)
1989/07/09 (C)
1992/06/19 1990/02/09 1991/08/26 1990/11/19 1992/03/27 1990/02/09 1991/08/01 1995/05/09 1995/05/09 1991/08/01 1995/07/17 1994/10/03 1991/08/01 1995/07/17 1990/02/09 1995/07/17
Reference [3] [2] [5] [2] [3] [3] [5] [2] [3] [19] [5] [3] [5] [6] [3] [5] [2] [5]

Optical Imaging

Component Brightness (Magnitudes)
F555W (V) F814W (I) F160W (H) r Spinrad R (rs) U
A 23.1±0.3 21.5±0.3 17.386±0.09


B 21.06±0.08 19.09±0.11 16.89±0.06


Lensing galaxy 21.9±0.4 19.51±0.17 17.1±0.1


Total


20.0 18.9 21.5
Instrument WFPC2 (HST) WFPC2 (HST) NIC1/NICMOS (HST) NOT 2.5-m Lick 3-m Lick 3-m
Integration time

7870 sec
in 6exp.
2200 sec 1200 sec 1800 sec
PSF size (arcsec) 0.65 0.79 0.131 1.0 2.1
1.5
1.5
Pixel scale (mas/pixel) 45.5 45.5 43 200

Date observed

1997/08/07 1991/11/07 1991/10/11
1991/12/13
1991/12/13
Reference no. [15] [15] [15] [2] [2] [2]

Radio Image Polarisations

Image Radio Polarisation(%) Polarisation angle(°)
8.4 GHz 8.4 GHz 15 GHz 22 GHz 22.4 GHz 8.4 GHz 8.4 GHz 15 GHz 22 GHz 22.4 GHz
A 6.4±0.1 6.4 10.5 10.1 10.8±0.5 46.6±2 46 73 58 74±10
B 8.1±0.1 8.0 9.4 9.4 9.6±0.5 105.7±2 108 90 63 80±10
Resolution (mas)
200 119x113


200 119x113

Map noise level









Instrument VLA VLA VLA VLA VLA VLA VLA VLA VLA VLA
Date observed 1990/02/09 1991/08/01 1991/08/01 1991/08/01 1990/02/09 1990/02/09 1991/08/01 1991/08/01 1991/08/01 1990/02/09
Reference no. [2] [3] [3] [3] [2] [2] [3] [3] [3] [2]

Redshifts

Object Redshift Instrument Date Observed Reference
Lens galaxy 0.6847 ISIS (WHT) 1992/10/29 [4]
Source 0.944±0.002 LRIS (Keck) 1994/09
1995
1996
1997
2000
[21]

Notes

  1. World's Smallest Einstein Ring (335 mas in diameter)

  2. Prime candidate for determination of H0, variable in radio and possibly optical, time delay measured by Biggs et al. (1999) to be 10.5±0.4 days, giving a value for H0 of 69+13-19 kms-1 Mpc-1

  3. Cohen et al. find a time delay of 10.1+1.5-1.6 days (95% confidence) from VLA measurements taken (independently) over same epoch as Biggs et al. (1999), and determine H0 = 71+17-23 km s-1 Mpc-1 for Ω0 = 1 and Λ0 = 0 (95% confidence, in absence of systematics).

  4. Difficulty in establishing position of lensing galaxy continues to limit attempts to model this system.

  5. Forthcoming observations with the ACS on the HST are designed to locate the lensing galaxy.

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 calibrator sources (1), A. R. Patnaik et al., Mon. Not. R. Astron. Soc. 254, pp. 655-676 (1992)


[2] Radio and optical observations of 0218+357 - The smallest Einstein ring?, C. P. O'Dea et al., Astron. J. (ISSN 0004-6256) 104, no. 4, 1320-1330 (1992)


[3] B0218+35.7: a gravitationally lensed system with the smallest separation, A. R. Patnaik et al., Mon. Not. R. Astron. Soc. 261, 435-444 (1993)


[4] The Redshift of the Lensing Galaxy in the Gravitationally Lensed System B:0218+35.7, I. W. A. Browne et al., Mon. Not. R. Astron. Soc. 263, L32 (1993)


[5] Frequency dependent radio structure of the gravitational lens system B0218+357, A. R. Patnaik and R. W. Porcas, H.R.R.L. (ASP Conf. Series Vol. 156) ISBN 1-886733-76-7, p. 247.


[6] VLBA observations of the gravitational lens system B0218+357, A. R. Patnaik et al., Mon. Not. R. Astron. Soc. 274, L5-L7 (1995)


[7] The optical appearance of the gravitational lens system B0218+357, F. Grundahl and J. Hjorth, Mon. Not. R. Astron. Soc. 275, L67-L71 (1995)


[8] A lens model for B0218+357, S. Nair, Astrophysical applications of gravitational lensing (173rd Symposium of the IAU p. 197) (1996)


[9] Radio measurement of the time delay in 0218+357, E. A. Corbett et al., Astrophysical applications of gravitational lensing (173rd Symposium of the IAU p.37) (1996)


[10] Observations of lens systems with Keck I, C. R. Lawrence et al., Astrophysical applications of gravitational lensing (173rd Symposium of the IAU p.299) (1996)


[11] Multi-frequency VLBI Observations of the Gravitational Lens B0218+ 357, R. W. Porcas and A. R. Patnaik, Extragalactic radio sources: proceedings of the 175th Symposium of the IAU p.115) (1996)


[12] PhD Thesis, A. D. Biggs (1999)


[13] Time delay for the gravitational lens system B0218+357, A. D. Biggs et al., Mon. Not. R. Astron. Soc. 304, 349-358 (1999)


[14] 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)


[15] NICMOS images of JVAS/CLASS gravitational lens systems, N. Jackson et al., Mon. Not. R. Astron. Soc. 311, pp. 389-396 (2000)


[16] Further Investigation of the Time Delay, Magnification Ratios, and Variability in the Gravitational Lens 0218+357, A. S. Cohen et al., Astrophys. J. 545, Iss. 2, pp. 578-590 (2000)


[17] MERLIN/VLA imaging of the gravitational lens system B0218+357, A. D. Biggs et al., Mon. Not. R. Astron. Soc. 322, p. 821 (2001)


[18] Intrinsic intraday variability in the gravitational lens system B0218+357, A. D. Biggs et al., Mon. Not. R. Astron. Soc. 323, pp. 995-998 (2001)


[19] Polarization VLBI Observations of the Gravitational Lens System B0218+357 at 8.4 GHz, A. J. Kemball et al., Astrophys. J. 562, p. 649 (2001)


[20] Global 8.4-GHz VLBI observations of JVAS B0218+357, A. D. Biggs et al., Accepted by Mon. Not. R. Astron. Soc. (astro-ph/0209182: 2002)


[21] The Redshift of the Lensed Object in the Einstein Ring B0218+357, J. G. Cohen, C. R. Lawrence and R. D. Blandford, Accepted by Astrophys. J. (astro-ph/0209457: 2002)

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