Public code

This section makes available some code that I have contributed to for past projects and that might be useful for other purposes, too. If you use a code in your work, I greatly appreciate your feedback, patches/improvements and referencing of related publications. In case of any questions, don't hesitate to contact me.

metacalibration / xshear

Hacked version of Erin Sheldon's xshear for use with metacalibration shape catalogs, on github. Selection bias corrections must be calculated and applied as a post-processing step.
Relevant publication: paper using this for DES Y1 cluster lensing

Cosmic variance of cluster density profiles

This is an implementation of the model described here. It predicts the variation of the projected density / convergence / gravitational shear profile of cluster haloes of fixed mass, based on three semi-analytic components: variation of halo concentration, ellipticity, and the presence or absence of correlated secondary haloes. The code can return the covariance matrix in convergence for any set of angular bins and at arbitrary redshift. Note that the model was fitted at z=0.25 and tested also at z=0.5 with a radial range of 1 to 30 arcmin and for 200m masses of 10^14 to 10^15 h^-1 solar -- outside that, you're extrapolating. The latest code can be found on github.
Relevant publications: paper describing the model

Clipped mean in SWarp

The code has been included in version 2.38 of SWarp and can be downloaded from the official Astromatic website. There are two small tools useful in combination with the clipped mean mode: MaskMap, which uses the list of outlier pixels this modified SWarp produces to generate single frame mask images, and PSFHomTest, which tests the homogeneity of your single frame PSFs to determine suitable clipping parameters such that the stack PSF is a linear combination of the single frame PSFs, both for download.
Relevant publications: paper describing the algorithm, first use in weak lensing science analysis, application to DES science verification data for cluster weak lensing.


GalSim is a galaxy image simulation toolkit in Python/C++ available here. I find it a very useful framework and have contributed to a module that simulates charge deflection, the so-called 'brighter/fatter' effect.
Relevant publications: description of GalSim, one of the underlying shear-relevant methods, description of the brighter/fatter effect, brighter/fatter in DECam and its effect on shape measurement.

Public data

This section provides some data from past publications for download. You are welcome to use it for your own work. More information is provided in the indicated source(s). Please e-mail me in case in of any questions or if you would like to use any data from my papers that is not provided below.


Data from DES analysis is provided here, including in particular the Y1 shear/photo-z catalogs, two-point function products, and density split statistics products.

MACS J0416.1-2403

see old website