Detection of Lens Candidates for the Double QSO Q2345+007

May, 1994
Published in:
  • Astrophys.J.Lett. 431 (1994) L71
e-Print:

Citations per year

19941997200020032006012345
Abstract: (arXiv)
Luminous objects associated with the 7.06\arcsec\ separation double quasar Q2345+007 have, until now, escaped detection. In this letter we present the results of the deepest known imaging of the region surrounding the quasar. The total exposure times were 47600 seconds in Bj_j (101 frames) and 32160 seconds in R (82 frames). The frames came from CFHT, CTIO, and KPNO. We detect a Bj_j = 25.0 mag galaxy (Bj_j -- R = 0.5 mag) in close proximity to the fainter QSO image, possibly at z=1.49z = 1.49 given by several absorption features in the QSO spectra. Furthermore, there is a 2.9σ\sigma enhancement in the number density of faint galaxies (2424 \le Bj_j 28\le 28, Bj_j- R 1.5 \le 1.5) near the quasar and another 3.1σ\sigma enhancement further away. These discoveries support the hypothesis that Q2345+007 is being lensed by one or more distant mass concentrations and may imply that compact ``clusters'' already exist at early epochs. We discuss several lens models for the system and the cosmological implications.