Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-12-16
Astrophys.J. 605 (2004) 78-97
Astronomy and Astrophysics
Astrophysics
21 pages, 24 figures, 5 tables, accepted for publication in ApJ
Scientific paper
10.1086/382221
We study the recently discovered gravitational lens SDSS J1004+4112, the first quasar lensed by a cluster of galaxies. It consists of four images with a maximum separation of 14.62''. The system has been confirmed as a lensed quasar at z=1.734 on the basis of deep imaging and spectroscopic follow-up observations. We present color-magnitude relations for galaxies near the lens plus spectroscopy of three central cluster members, which unambiguously confirm that a cluster at z=0.68 is responsible for the large image separation. We find a wide range of lens models consistent with the data, but they suggest four general conclusions: (1) the brightest cluster galaxy and the center of the cluster potential well appear to be offset by several kpc; (2) the cluster mass distribution must be elongated in the North--South direction, which is consistent with the observed distribution of cluster galaxies; (3) the inference of a large tidal shear (~0.2) suggests significant substructure in the cluster; and (4) enormous uncertainty in the predicted time delays between the images means that measuring the delays would greatly improve constraints on the models. We also compute the probability of such large separation lensing in the SDSS quasar sample, on the basis of the CDM model. The lack of large separation lenses in previous surveys and the discovery of one in SDSS together imply a mass fluctuation normalization \sigma_8=1.0^{+0.4}_{-0.2} (95% CL), if cluster dark matter halos have an inner slope -1.5. Shallower profiles would require higher values of \sigma_8. Although the statistical conclusion might be somewhat dependent on the degree of the complexity of the lens potential, the discovery is consistent with the predictions of the abundance of cluster-scale halos in the CDM scenario. (Abridged)
Annis James
Bahcall Neta A.
Becker Robert H.
Brinkmann John
Castander Francisco J.
No associations
LandOfFree
Observations and Theoretical Implications of the Large Separation Lensed Quasar SDSS J1004+4112 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Observations and Theoretical Implications of the Large Separation Lensed Quasar SDSS J1004+4112, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Observations and Theoretical Implications of the Large Separation Lensed Quasar SDSS J1004+4112 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-591879