The shape of relaxed galaxy clusters and the public release of a HST
  shape measurement code, pyRRG
  We study the shape of eight dynamically relaxed galaxy clusters observed with
the Hubble Space Telescope and Chandra X-Ray Observatory. Using strong and weak
gravitational lensing, the shape of the Brightest Cluster Galaxy and the X-ray
isophote we study the ellipticity of the cluster halo at four different radii.
We find that the proxies probing the inner regions of the cluster are strongly
coupled with the BCG shape correlated with both the shape predicted by strong
gravitational lensing and the X-ray isophote. Conversely we find no such
correlation between the shape as predicted by the weak lensing and the other
three probes suggesting any coupling between the inner and outer regions is
weak. We also present in this paper the public release of the HST weak lensing
shape measurement code pyRRG, directly available from PyPi
(https://pypi.org/project/pyRRG/). This python3.7 code, based on Rhodes et al.
(2000) adopts an automated star-galaxy classifier based on a Random Forest and
outputs scientifically useful products such as weak lensing catalogues suitable
for the mass mapping algorithm Lenstool.
