Discovery of a Probable Gravitational Lens [chapter]

G. Meylan, S. Djorgovski
1989 Active Galactic Nuclei  
We report the discovery of a new probable gravitational lens system, associated with the quasar UM 425 = 1120+019, at ζ = 1.465. The optical image of the system consists of 4 or more components. The two wellobserved brightest components have very similar spectra. The difference of the two spectra (scaled appropriately) is consistent with a spectrum of a galaxy at ζ ~ 0.6. There is a large number of faint galaxies in the field, suggestive of a lensing cluster at that redshift. The quasar UM 425
more » ... The quasar UM 425 has been selected for an optical imaging search for gravitational lenses, due to its moderately high redshift (ζ ~ 1.49) and the apparently large luminosity, both of which make it a good a priori case for gravito-optical magnification. The survey is described in more detail in the companion paper by Djorgovski & Meylan. Figure 1: A section of a V + R stack image of the UM 425 field, obtained at CTIO. The field shown is 50x50 arcsec, with north to the top, east to the left. The components of the UM 425 system are indicated with the letters. The isophotal levels are spaced logarithmically in factors of 2. Multicolor CCD images of the object, obtained at CTIO in March of 1987 ( Figure 1) show several close companions (within 3 to 6 arcsec), whose BVR colors 271 D. Ε. Ο sterbrock and J. S. Miller (eds.), Active Galactic Nuclei, 271-272. ©1989 by the IAU. use, available at https://www.cambridge.org/core/terms. https://doi.
doi:10.1007/978-94-009-0963-2_81 fatcat:5g5biuvexffafiovev3ggdll3u