A new quadruple gravitational lens system: CLASS B0128+437Phillips, PM., Norbury, MA., Koopmans, LVE., Browne, IWA., Jackson, NJ., Wilkinson, PN., Biggs, AD., Blandford, RD., de Bruyn, AG., Fassnacht, CD., Helbig, P., Mao, S., Marlow, DR., Myers, ST., Pearson, TJ., Readhead, ACS., Rusin, D. & Xanthopoulos, E., 1-Dec-2000, In : Monthly Notices of the Royal Astronomical Society. 319, 2, p. L7-L11 5 p.
Research output: Contribution to journal › Article › Academic › peer-review
High-resolution MERLIN observations of a newly discovered four-image gravitational lens system, B0128+437, are presented. The system was found after a careful re-analysis of the entire CLASS data set. The MERLIN observations resolve four components in a characteristic quadruple-image configuration; the maximum image separation is 542 mas and the total flux density is 48 mJy at 5 GHz. A best-fitting lens model with a singular isothermal ellipsoid results in large errors in the image positions. A significantly improved fit is obtained after the addition of a shear component, suggesting that the lensing system is more complex and may consist of multiple deflectors. The integrated radio spectrum of the background source indicates that it is a gigahertz peaked spectrum source, It may therefore be possible to resolve structure within the radio images with deep VLBI observations and thus to constrain the lensing mass distribution better.
|Number of pages||5|
|Journal||Monthly Notices of the Royal Astronomical Society|
|Publication status||Published - 1-Dec-2000|
- quasars : individual : B0128+437, cosmology : observations, gravitational lensing, PHASE CALIBRATION SOURCES, VLA ASTROMETRIC SURVEY, RADIO-SOURCES, SKY SURVEY, STATISTICS