scholarly journals VLBI Observations of the Gravitational Lens System 2016+112

1988 ◽  
Vol 129 ◽  
pp. 209-210
Author(s):  
M. B. Heflin ◽  
M. V. Gorenstein ◽  
E. E. Falco ◽  
I. I. Shapiro ◽  
B. F. Burke ◽  
...  
Keyword(s):  
Flux Density ◽  
Model Fitting ◽  
Gravitational Lens ◽  
Vlbi Observation ◽  
Lens System ◽  
Vlbi Observations

On June 1, 1984 we conducted a seven station 18-cm VLBI observation of the 2016+112 gravitational lens system. Preliminary brightness distributions for A and B have been obtained via model fitting. Weak correlated flux density was detected in the C component region.

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

1988 ◽  
Vol 129 ◽  
pp. 201-206
Author(s):  
M. V. Gorenstein ◽  
R. J. Bonometti ◽  
N. L. Cohen ◽  
E. E. Falco ◽  
I. I. Shapiro ◽  
...  
Keyword(s):  
Time Delay ◽  
Flux Density ◽  
Gravitational Lens ◽  
Time Variability ◽  
Lens System ◽  
Relative Time ◽  
Vlbi Observations ◽  
New Information ◽  
Superluminal Motion ◽  
Upper Limits

A series of VLBI observations of the gravitational lens system 0957+561 at λ13 cm has yielded the positions of the A and B images, the relative magnification of their largest discernible radio structures, and the time variability of their smallest discernible radio structures. These observations have also allowed upper limits to be placed on the flux density of an expected third image. The positions and relative magnification of the A and B images provide new information with which to constrain models of the lens that forms the images. The detection of variations in the flux densities of the cores of A and B suggests that observations at shorter wavelengths may reveal superluminal motion, which may in turn provide a means to measure the relative time delay.

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 Search for Radio Recombination Lines towards the Gravitational Lens PKS1830-211

2002 ◽  
Vol 199 ◽  
pp. 116-117
Author(s):  
N.R. Mohan ◽  
K.R. Anantharamaiah ◽  
W.M. Goss
Keyword(s):  
Flux Density ◽  
Emission Measure ◽  
Gravitational Lens ◽  
Lens System ◽  
Frequency Range ◽  
Ionized Gas ◽  
Density Measurements ◽  
Radio Recombination Lines ◽  
Upper Limits ◽  
Single Epoch

A search for radio recombination lines near 20 cm at z=0.193 and z=0.886 towards the gravitational lens system PKS1830-211 has yielded upper limits of |τL| ≤ 5 × 10−5 and ≤ 5 × 10−4 at the two redshifts respectively. Based on the non-detections, we derive upper limits to the emission measure of the ionized gas in the absorbing systems. We also present continuum flux density measurements over the frequency range 0.3—45 GHz made at a single epoch.

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

scholarly journals The Structure of the Gravitational Lens System B1152+199

2001 ◽  
Vol 18 (2) ◽  
pp. 172-175 ◽  
Author(s):  
P. G. Edwards ◽  
J. E. J. Lovell ◽  
H. Hirabayashi ◽  
D. L. Jauncey ◽  
S. Toft
Keyword(s):  
Time Delay ◽  
Time Variation ◽  
Model Fitting ◽  
Gravitational Lens ◽  
Lens System ◽  
Compact Array

AbstractWe have commenced a program to monitor the gravitational lens B1152+199 with the Australia Telescope Compact Array (ATCA) to search for variability of the lensed components with the goal of measuring the lensing time delay. As part of this program we made a 9 hour full-synthesis observation in June 2000 to derive a ‘template’ for model-fitting the shorter, multi-epoch, monitoring observations. We report here on the results of this full-synthesis observation and on three additional epochs of monitoring for time variation.

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