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Published August 1999 | Version Published
Journal Article Open

CLASS B1555+375: A New Four-Image Gravitational Lens System

Creators

  • 1. ROR icon University of Pennsylvania
  • 2. ROR icon University of Manchester
  • 3. ROR icon National Radio Astronomy Observatory
  • 4. ROR icon California Institute of Technology
  • 5. ROR icon University of Groningen
  • 6. ROR icon Netherlands Institute for Radio Astronomy

Abstract

We have discovered a new gravitational lens in the Cosmic Lens All-Sky Survey. The lens B1555+375 is a four-image system with a maximum separation of 0."42. VLA and MERLIN radio observations show these images in a characteristic quadruple-lens configuration. Optical imaging with the Keck II Telescope at R band shows a faint extended object. We estimate the combined emission from the lens and background source to be R = 25 mag. Observations at H band with the William Herschel Telescope also detected this extended object. The combined lens and background source magnitude was measured to be H = 19 mag. Presently, redshifts for both the lensing galaxy and background source are undetermined. We conclude that one or more of the following are true: the lens galaxy is sub-L*, it has z > 0.5, or it is highly reddened. The observed MERLIN component positions and flux densities can be well described by a lens model based on a singular isothermal ellipsoid mass distribution. Our best-fit lens model has a reduced χ^2 of 2.6. High-resolution VLA radio observations should help to constrain the lens model further.

Additional Information

© 1999 The American Astronomical Society. Received 1999 April 7; accepted 1999 April 29. Based on observations made with the National Radio Astronomy Observatory (NRAO), which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. ; with the Multi-Element Radio-linked Interferometer Network (MERLIN), which is a national facility operated by the Nuffield Radio Astronomy Laboratories, Jodrell Bank, University of Manchester, on behalf of the UK Particle Physics and Astronomy Research Council; with the William Herschel Telescope (WHT), which is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias; and with the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Keck Observatory was made possible by the generous financial support of the W. M. Keck Foundation. We wish to thank P. J. Helbig for assistance with this work. We also thank the anonymous referee for helpful suggestions on how to improve the paper. S. T. M. is supported by an Alfred P. Sloan fellowship. This research was supported in part by the European Commission, TMR Programme, research network contract ERBFMRXCT96-0034 "CERES."

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Additional details

Identifiers

Eprint ID
96094
Resolver ID
CaltechAUTHORS:20190604-073058404

Funding

W. M. Keck Foundation
Alfred P. Sloan Foundation
Marie Curie Fellowship
ERBFMRXCT96-0034

Dates

Created
2019-06-04
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Updated
2023-01-19
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