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Published August 2001 | Published + Accepted Version
Journal Article Open

The New Two-Image Gravitational Lens System CLASS B2319+051


We report the discovery of a new two-image gravitational lens system, CLASS B2319+051, from the Cosmic Lens All-Sky Survey. Radio imaging with the Very Large Array (VLA) and Multielement Radio-linked Interferometer Network (MERLIN) shows two compact components with a flux density ratio of ≃5 : 1, separated by 1."36. Observations with the Very Long Baseline Array (VLBA) resolve each of the radio components into a pair of parity-reversed subcomponents. Hubble Space Telescopeobservations with the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) show a bright elliptical galaxy (G1) coincident with the radio position, and a second irregular galaxy (G2) 3."4 to the northwest. Previous spectroscopic studies have indicated that these galaxies are at different redshifts (z_(G1) = 0.624, z_(G2) = 0.588). Infrared counterparts to the lensed radio components are not detected in the NICMOS image, and the source redshift has not yet been determined. Preliminary mass modeling based on the VLBA subcomponent data indicates that the lensing potential includes a strong external shear contribution. A VLA monitoring program is currently being undertaken to measure the differential time delay.

Additional Information

© 2001 The American Astronomical Society. Received 2000 October 1; accepted 2001 May 2. We thank the staffs of the VLA, MERLIN, and VLBA for their assistance during our observing runs. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. MERLIN is operated as a National Facility by the University of Manchester, on behalf of the UK Particle Physics and Astronomy Research Council. This research used observations with the Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by Associated Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. D. R. acknowledges funding from the Zaccheus Daniel Foundation. This work was supported in part by European Commission TMR Programme, Research Network Contract ERBFMRXCT 96-0034 CERES.

Attached Files

Published - Rusin_2001_AJ_122_591.pdf

Accepted Version - 0104399.pdf


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August 19, 2023
October 20, 2023