116 research outputs found
Weak lensing mass distributions for 24 X-Ray Abell Clusters
We use the weak gravitational lensing effect to study the mass distribution
and dynamical state of a sample of 24 X-ray luminous clusters of galaxies
() observed with the VLT-FORS1 under homogeneous sky conditions
and subarsecond image quality. The galaxy shapes were measured after
deconvolution with a locally determined point-spread-function, while the
two-dimensional mass distributions of the clusters were computed using an
algorithm based on the maximum entropy method. By comparing the mass and light
distributions of the clusters in our sample, we find that their mass centers,
for the majority of the clusters, is consistent with the positions of optical
centers. We find that some clusters present significant mass substructures
which generally have optical counterparts. At least in one cluster (Abell
1451), we detect a mass substructure without an obvious luminous counterpart.
The radial profile of the shear of the clusters was fitted using circular and
elliptical isothermal elliptical distributions, which allowed the finding of a
strong correlation between the orientation of the major-axis of the matter
distribution and the corresponding major-axes of the brightest cluster galaxy
light-profiles. Estimates of how close to dynamical relaxation are these
clusters were obtained through comparison of our weak-lensing mass measurements
with the x-ray and velocity dispersion determinations available in the
literature. We find that clusters with intra-cluster gas colder than 8 keV show
a good agreement between the different mass determinations, but clusters with
gas hotter than 8 keV present discrepant mass values.Comment: 23 pages, 8 figures. Submitted to ApJ A version of this paper with
all the figures of the appendix A can be found at
http://www.astro.iag.usp.br/~eduardo/shear.ps.g
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