Revisiting CFHTLenS cosmic shear: Optimal E/B mode decomposition using
  COSEBIs and compressed COSEBIs
  We present a re-analysis of the CFHTLenS weak gravitational lensing survey
using Complete Orthogonal Sets of E/B-mode Integrals, known as COSEBIs. COSEBIs
provide a complete set of functions to efficiently separate E-modes from
B-modes and hence allow for robust and stringent tests for systematic errors in
the data. This analysis reveals significant B-modes on large angular scales
that were not previously seen using the standard E/B decomposition analyses. We
find that the significance of the B-modes is enhanced when the data is split by
galaxy type and analysed in tomographic redshift bins. Adding tomographic bins
to the analysis increases the number of COSEBIs modes, which results in a less
accurate estimation of the covariance matrix from a set of simulations. We
therefore also present the first compressed COSEBIs analysis of survey data,
where the COSEBIs modes are optimally combined based on their sensitivity to
cosmological parameters. In this tomographic CCOSEBIs analysis we find the
B-modes to be consistent with zero when the full range of angular scales are
considered.
