VLBI Observations of the 0957+561 Gravitational Lens System

1988 ◽  
pp. 201-206 ◽  
Author(s):  
M. V. Gorenstein ◽  
R. J. Bonometti ◽  
N. L. Cohen ◽  
E. E. Falco ◽  
I. I. Shapiro ◽  
...  
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Vlbi Observations

scholarly journals Can We Measure H0 with VLBI Observations of Gravitational Images?

1988 ◽  
Vol 129 ◽  
pp. 207-208
Author(s):  
E. E. Falco ◽  
M. V. Gorenstein ◽  
I. I. Shapiro
Keyword(s):  
Time Delay ◽  
Mass Distribution ◽  
Velocity Dispersion ◽  
Gravitational Lens ◽  
Lens System ◽  
Relative Time ◽  
Surface Mass ◽  
A Value ◽  
Vlbi Observations ◽  
The Difference

We have used the relative positions and magnifications of the A and B images in the gravitational lens system 0957+561, obtained from VLBI observations, to constrain a model for the surface mass distribution of the lens. With measurements of the difference ΔτBA in propagation times associated with A and B (the “relative time delay”) and of the velocity dispersion of the main lensing galaxy, both to be obtained, our model will yield a value for H0 with an uncertainty of ∼ 20% due mainly to uncertainties in our assumptions.

scholarly journals VLBI Observations of Gravitational Lens Systems

1988 ◽  
Vol 129 ◽  
pp. 191-199
Author(s):  
Edwin L. Turner
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Additional Test ◽  
System A ◽  
Vlbi Observations ◽  
Vlbi Data ◽  
Cosmological Tests ◽  
Superluminal Expansion ◽  
Additional Constraints

Four specific and particularly powerful types of possible VLBI lens studies are discussed. First, comparison of mas scale structure in putative pairs of images separated by arc seconds can provide a powerful additional test of the lens hypothesis in specific candidate systems. Second, VLBI searches for lens systems with image separations too small for resolution by optical or VLA searches will limit (or even determine!) the cosmological density of condensed objects with individual masses ∼ 106M⊙. Third, study of multiply imaged superluminal expansion events will allow a determination of the light travel time delay between different images in a lens system, a quantity which is quite difficult to measure by other means but which would allow profound cosmological tests. Fourth, VLBI data can be used to determine relative image parities and even the full magnification matrix of various images in a lens system, thus providing powerful additional constraints on detailed lens models. Finally, the speculative possibility of detecting Galactic stellar lensing events using VLBI techniques is discussed.

scholarly journals VLBI Observations of the Gravitational Lens System 0957+561

1995 ◽  
Vol 110 ◽  
pp. 2566 ◽  
Author(s):  
R. M. Campbell ◽  
J. Lehar ◽  
B. E. Corey ◽  
I. I. Shapiro ◽  
E. E. Falco
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Vlbi Observations

First epoch VLBI observations of the gravitational lens system 2016+112

2006 ◽  
pp. 136-140
Author(s):  
M. B. Heflin ◽  
M. V. Gorenstein ◽  
C. R. Lawrence ◽  
B. F. Burke ◽  
I. I. Shapiro
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Vlbi Observations

VLBI Observations of the Gravitational Lens System 2016+112

1988 ◽  
pp. 209-210 ◽  
Author(s):  
M. B. Heflin ◽  
M. V. Gorenstein ◽  
E. E. Falco ◽  
I. I. Shapiro ◽  
B. F. Burke ◽  
...  
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Vlbi Observations

Polarization VLBI Observations of the Gravitational Lens System B0218+357 at 8.4 GHz

2001 ◽  
Vol 562 (2) ◽  
pp. 649-653 ◽  
Author(s):  
A. J. Kemball ◽  
A. R. Patnaik ◽  
R. W. Porcas
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Vlbi Observations

scholarly journals Global VLBI observations of the gravitational lens system 0957+561 A,B

1994 ◽  
Vol 270 (2) ◽  
pp. 457-464 ◽  
Author(s):  
M. A. Garrett ◽  
R. J. Calder ◽  
R. W. Porcas ◽  
L. J. King ◽  
D. Walsh ◽  
...  
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Vlbi Observations

VLBI observations of the gravitational lens system 0957+561 - Structure and relative magnification of the A and B images

1988 ◽  
Vol 334 ◽  
pp. 42 ◽  
Author(s):  
M. V. Gorenstein ◽  
N. L. Cohen ◽  
I. I. Shapiro ◽  
A. E. E. Rogers ◽  
R. J. Bonometti ◽  
...  
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Vlbi Observations

First- and second-epoch VLBI observations of the gravitational lens system 2016 + 112

1991 ◽  
Vol 378 ◽  
pp. 519 ◽  
Author(s):  
M. B. Heflin ◽  
M. V. Gorenstein ◽  
C. R. Lawrence ◽  
B. F. Burke
Keyword(s):  
Gravitational Lens ◽  
Lens System ◽  
Vlbi Observations

scholarly journals Multi-frequency VLBI Observations of the Gravitational Lens B0218+357

1996 ◽  
Vol 175 ◽  
pp. 115-117
Author(s):  
R. W. Porcas ◽  
A. R. Patnaik
Keyword(s):  
Time Delay ◽  
Mass Distribution ◽  
Hubble Constant ◽  
Gravitational Lens ◽  
Radio Sources ◽  
Constant Independent ◽  
Lens System ◽  
Vlbi Observations ◽  
Spectrum Radio ◽  
Simple Mass

The gravitational lens system B0218+357 comprises 2 image components (A and B) and a radio ‘Einstein Ring’ (Patnaik et al, 1993). The redshift of the lens galaxy is 0.6847 (Browne et al, 1994) and that of the imaged source 0.96 (preliminary result; Lawrence et al, 1995). The separation of A and B, which are both flat-spectrum radio sources, is only 0.335 arcsec, leading to the hope that the lens is a single galaxy with a relatively simple mass distribution. Refsdal pointed out (1964) that a model of such a distribution, and a measurement of the time difference along the two image paths, leads to an estimate of the Hubble constant, independent of the usual steps in the distance ladder. B0218+357 is one of only a few lensed systems well suited for such measurements. A preliminary value of 12 days has been measured for the A-B time delay, derived from a comparison of the percentage polarisation variations of the images at 15GHz, using the VLA (Corbett et al, 1995).

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