RX J0911+05: A Massive Cluster Lens at [ITAL]z[/ITAL] = 0.769

Open Access
Publisher Website
Google Scholar
Abstract
We report the detection of a massive high-redshift cluster of galaxies near the quadruple quasar RX J0911+05, using the Low-Resolution Imaging Spectrograph instrument on the Keck II telescope. The cluster is found to have a mean redshift of = 0.7689 ± 0.002 and a velocity dispersion of σ = 836 km s-1, based on redshift measurements for 24 member galaxies. This massive high-redshift cluster is the origin of the unusually large external shear required by lensing models of the quadruple quasar system. We predict the expected time delay depending on the exact contribution of the cluster. A measurement of the time delay and further deep lensing and X-ray observations will unravel useful properties of this serendipitously discovered high-redshift cluster and may put interesting cosmological constraints on H0.
All Related Versions