NEAR-INFRARED IMAGES OF MG 1131-0456 WITH THE KECK,W.M. TELESCOPE - ANOTHER DUSTY GRAVITATIONAL LENS

Images of the gravitational lens system MG 1131+0456 taken with the ne ar-infrared camera on the W. M. Keck telescope in the J and K-s bands show that the infrared counterparts of the compact radio structure are exceedingly red, with J-K > 4.2 mag. The J image reveals only the len sing galaxy, while the K-s image shows both the lens and the infrared counterparts of the compact radio components. After subtracting the le nsing galaxy from the K-s image, the position and orientation of the c ompact components agree with their radio counterparts. The broad-band spectrum and observed brightness of the lens suggest a giant galaxy at a redshift of similar to 0.75, while the color of the quasar images s uggests significant extinction by dust in the lens. There is a signifi cant excess of faint objects within 20'' of MG 1131+0456. Depending on their mass and redshifts, these objects could complicate the lensing potential considerably.