SDSS J1029+2623: A Gravitationally Lensed Quasar with an Image Separation of 22.5 Arcseconds

Naohisa Inada, Masamune Oguri, Tomoki Morokuma, Mamoru Doi, Naoki Yasuda, Robert H. Becker, Gordon T. Richards, Christopher S. Kochanek, Issha Kayo, Kohki Konishi, Hiroyuki Utsunomiya, Min-Su Shin, Michael A. Strauss, Erin S. Sheldon, Donald G. York, Joseph F. Hennawi, Donald P. Schneider, Xinyu Dai, Masataka Fukugita

Published 2006-11-08Version 1

We report the discovery of a cluster-scale lensed quasar, SDSS J1029+2623, selected from the Sloan Digital Sky Survey. The lens system exhibits two lensed images of a quasar at z_s=2.197. The image separation of 22.5" makes it the largest separation lensed quasar discovered to date. The similarity of the optical spectra and the radio loudnesses of the two components support the lensing hypothesis. Images of the field show a cluster of galaxies at z_l~0.55 that is responsible for the large image separation. The lensed images and the cluster light center are not collinear, which implies that the lensing cluster has a complex structure.