TOWARD ESTIMATION OF H(0) FROM VLBI OBSERVATIONS OF THE GRAVITATIONAL LENS SYSTEM-0957+561

DOI: 
10.1086/174084
Publication date: 
10/05/1994
Main author: 
CAMPBELL, RM
IAA authors: 
Authors: 
CAMPBELL, RM; COREY, BE; FALCO, EE; SHAPIRO, II; GORENSTEIN, MV; ELOSEGUI, P; MARCAIDE, JM; ALVI, K
Journal: 
ASTROPHYSICAL JOURNAL
Refereed: 
Yes
Publication type: 
Article
Volume: 
426
Pages: 
486-492
Number: 
Abstract: 
We have analyzed two epochs of 6 cm VLBI observations of the two brightest images, A and B, of the gravitationally lensed quasar 0957+561 in a search for correlated structural evolution from which to estimate DELTAtau(BA) the difference in propagation time for light traveling between the quasar and Earth along the paths corresponding to these two images. However, we detected only marginal increases in the separation between the core and the innermost jet component in each image over the 2 year interval 1987-1989. Because monitoring image brightness variations has since led to apparently reliable estimates of DELTAtau(BA), we intend to use spatial variations in the relative magnification field across the extent of the images to constrain further the mass distribution of the lens, which is now the principal contributor to the uncertainty in estimates of H0 from this lens system.
Database: 
WOK
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/1994ApJ...426..486C/abstract
ADS Bibcode: 
1994ApJ...426..486C
Keywords: 
DISTANCE SCALE; GRAVITATIONAL LENSING; QUASARS, INDIVIDUAL (0957 + 561); TECHNIQUES, INTERFEROMETRIC