Testing Hydrostatic Equilibrium in Galaxy Clusters using X-ray and Optical Observations
Date Issued
2010
Date
2010
Author(s)
I-Non, Chiu
Abstract
We test the hydrostatic equilibrium in galaxy clusters with studying CHANDRA
X-ray observations and results of optical analysis of 8 relaxed clusters. We nd
that the contribution of non-thermal pressures is considerable and varying with
the distance to the clusters'' centres by investigating the pressure ratio pro les.
We conclude that the hydrostatic equilibrium assumption is not appropriate for
determining clusters'' mass accurately. However, because of the lack of accurate
strong gravitational lensing studies, we are not able to probe whether there is a
di erence of non-thermal pressure contribution at small radii between cool core
(CC) and non-cool core (NCC) clusters. And we nd that Abell 1689 is not a typical
relaxed cluster due to its pressure ratio pro le, which is very di erent to other 2
pressure ratio pro les derived with combined strong and weak lensing information.
For future work on the distribution of non-thermal pressure contribution, we suggest
that studying with more general models on combined strong and weak lensing is
necessary.
Subjects
Galaxy Cluster : A1689
Strong lensing
Weak lensing
X-ray
Type
thesis
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