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Astron. Astrophys. 346, 392-396 (1999)

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Dual-frequency VLBI observations of the gravitational lens system PKS 1830-211

J.C. Guirado 1, D.L. Jones 2, L. Lara 3, J.M. Marcaide 1, R.A. Preston 2, A.P. Rao 4 and W.A. Sherwood 5

1 Departamento de Astronomía, Universitat de València, E-46100 Burjassot, Valencia, Spain
2 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
3 Instituto de Astrofísica de Andalucía, CSIC, Apdo. Postal 3004, E-18080 Granada, Spain
4 National Centre for Radio Astrophysics, Tata Institute, Pune 411007, India
5 Max-Planck-Institut fuer Radioastronomie, D-53121 Bonn, Germany

Received 13 August 1998 / Accepted 9 March 1999


From simultaneous 8.4 and 2.3 GHz VLBA observations we have studied the morphology and properties of the compact components of the gravitational lens PKS 1830-211. We have found that the size of the southwest component increases as [FORMULA], most probably due to scattering by interstellar plasma, while the size of the northeast component does not increase with such wavelength dependence. The small separation between both lensed components, compared with the typical size of scattering clumps in our Galaxy, suggests that the scattering material is located in the lensing galaxy, rather than in the Milky Way. Within the uncertainties, the flux-density ratios of the brightest feature in the two compact components for the two frequency bands agree with each other, as expected for images of the same background feature.

Key words: cosmology: gravitational lensing – galaxies: quasars: individual: PKS 1830-211

Send offprint requests to: J.C. Guirado (jcg@vlbi.uv.es)

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© European Southern Observatory (ESO) 1999

Online publication: May 21, 1999