Near-infrared images of MG 1131+0456 with the W. M. Keck telescope: Another dusty gravitational lens?
Images of the gravitational lens system MG 1131+0456 taken with the near-infrared camera on the W. M. Keck telescope in the J and Ks bands show that the infrared counterparts of the compact radio structure are exceedingly red, with J - K greater than 4.2 mag. The J image reveals only the lensing galaxy, while the Ks image shows both the lens and the infrared counterparts of the compact radio components. After subtracting the lensing galaxy from the Ks image, the position and orientation of the compact components agree with their radio counterparts. The broad-band spectrum and observed brightness of the lens suggest a giant galaxy at a redshift of approximately 0.75, while the color of the quasar images suggests significant extinction by dust in the lens. There is a significant excess of faint objects within 20 sec of MG 1131+0456. Depending on their mass and redshifts, these objects could complicate the lensing potential considerably.
© 1994 American Astronomical Society. Received 1993 July 13; accepted 1993 October 12. The W. M. Keck Observatory is operated as a scientific partnership between the California Institute of Technology and the University of California. It was made possible by the generous gift of the W. M. Keck Foundation, and the support of its president, Howard Keck. We are most grateful for their visionary endowment that has made possible the first of the next generation of telescopes. It is a pleasure to also thank E. Stone, W. Frazier, W. Sargent, S. Faber and all of the many devoted people whose unflagging efforts have made possible the success of the W. M. Keck Observatory. We thank Jeremy Mould for useful discussions, Pat McCarthy for useful discussions and the results of stellar synthesis models, and an anonymous referee for helpful suggestions. Infrared and radio astronomy at Caltech are supported in part by grants from the NSF and NASA.
Published - 1994ApJ___420L___9L.pdf