2000/11/07 by A. D. Biggs, I. W. A. Browne, T. W. B. Muxlow +1 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2001.04176.x
published as Mon.Not.Roy.Astron.Soc. 322 (2001) 821 · Accepted for publication in MNRAS. 6 pages, 4 included PostScript figures
arxiv created 2000/11/07 · openalex publication_date 2001/04/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Gravitational lenses offer the possibility of accurately determining the Hubble parameter (H0) over cosmological distances, and B0218+357 is one of the most promising systems for an application of this technique. In particular this system has an accurately measured time delay (10.5±0.4 d) and preliminary mass modelling has given a value for H0 of 69+13−19 km s−1 Mpc−1. The error on this estimate is now dominated by the uncertainty in the mass modelling. As this system contains an Einstein ring it should be possible to constrain the model better by imaging the ring at high resolution. To achieve this we have combined data from MERLIN and the Very Large Array (VLA) at a frequency of 5 GHz. In particular MERLIN has been used in multifrequency mode in order to improve substantially the aperture coverage of the combined data set. The resulting map is the best that has been made of the ring and contains many new and interesting features. Efforts are currently underway to exploit the new data for lensing constraints using the LensClean algorithm.