2009ApJ...697.1793N -
Astrophys. J., 697, 1793-1804 (2009/June-1)
Improved constraints on the gravitational lens Q0957+561. I. Weak lensing.
NAKAJIMA R., BERNSTEIN G.M., FADELY R., KEETON C.R. and SCHRABBACK T.
Abstract (from CDS):
Attempts to constrain the Hubble constant using the strong gravitational lens system Q0957+561 are limited by systematic uncertainties in the mass model, since the time delay is known very precisely. One important systematic effect is the mass-sheet degeneracy, which arises because strong lens modeling cannot constrain the presence or absence of a uniform mass sheet κ, which rescales H0 by the factor (1 - κ). In this paper, we present new constraints on the mass sheet derived from a weak-lensing analysis of the Hubble Space Telescope imaging of a 6 arcmin square region surrounding the lensed quasar. The average mass sheet within a circular aperture (the strong lens model region) is constrained by integrating the tangential weak gravitational shear over the surrounding area. We find the average convergence within a 30'' radius around the lens galaxy to be κ(<30'') = 0.166 ±0.056 (1σ confidence level), normalized to the quasar redshift. This includes contributions from both the lens galaxy and the surrounding cluster. We also constrain a few other low-order terms in the lens potential by applying a multipole aperture mass formalism to the gravitational shear in an annulus around the strong-lensing region. Implications for strong lens models and the Hubble constant are discussed in an accompanying paper.
Abstract Copyright:
∼
Journal keyword(s):
galaxies: clusters: individual: Q0957+561 - galaxies: halos - gravitational lensing
Simbad objects:
4
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2009ApJ...697.1793N and select 'bookmark this link' or equivalent in the popup menu