The Shear TEsting Programme STEP
STEP is a collaborative project
to improve the accuracy and reliability of
all weak gravitational lensing measurements in preparation for the next
generation of wide-field surveys.
lensing provides an unbiased method to study the
distribution of dark matter
in the Universe. Measurements of weak lensing by
large scale structure, also known as cosmic shear, additionally
allows one to probe the evolution of dark matter providing
constraints on the properties of dark energy.
Technically, weak lensing is rather challenging to detect, with
the accuracy of any analysis depending critically
on the correction for instrumental distortions and atmospheric seeing.
These effects can
introduce distortions that are up to an order of
magnitude larger than the underlying weak shear distortion that we
wish to detect.
The unique qualities of weak lensing as a dark matter and dark energy probe
demand that all technical challenges are met and overcome, and
this desire has lead to the development of some of the most innovative
methods in astronomy.
STEP was launched in order to test and improve the
accuracy and reliability of all these methods through the rigorous
testing of shear measurement pipelines, the exchange of data and the sharing of
technical and theoretical knowledge within the weak lensing community. Our
current projects include
- The blind analysis of simulated images of ground-based
relatively simple galaxy morphologies.
- The blind analysis of simulated images of ground and space-based
observations of complex galaxy morphologies.
- Co-ordinated analysis of shared survey data.
If you are interested in joining the STEP collaboration
please e-mail Catherine