New near-infrared observations and lens-model constraints for UM673

E. Koptelova, T. Chiueh, W. P. Chen, H. H. Chan

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Aims. We performed a detailed photometric analysis of the lensed system UM673 (Q0142-100) and an analysis of the tentative lens models. Methods. High-resolution adaptive optics images of UM673 taken with the Subaru telescope in the H band were examined. We also analysed the J, H and K-band observational data of UM673 obtained with the 1.3 m telescope at the CTIO observatory. Results. We present photometry of quasar components A and B of UM673, the lens, and the nearby bright galaxy using H-band observational data obtained with the Subaru telescope. Based on the CTIO observations of UM673, we also present J- and H-band photometry and estimates of the J, H and K-band flux ratios between the two UM673 components in recent epochs. The near-infrared fluxes of the A and B components of UM673 and their published optical fluxes are analysed to measure extinction properties of the lensing galaxy. We estimate the extinction-corrected flux ratio between components A and B to be about 2.14 mag. We discuss lens models for the UM673 system constrained with the positions of the UM673 components, their flux ratio, and the previously measured time delay.

Original languageEnglish
Article numberA36
JournalAstronomy and Astrophysics
StatePublished - Jun 2014


  • Gravitational lensing: strong
  • Methods: data analysis
  • Quasars: individual: UM673


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