DSF¶
Delta Sigma forecasting tools for LSST DESC galaxy-galaxy lensing analyses.
DSF is a modelling package for projected galaxy-galaxy lensing observables, with a focus on \(\Delta\Sigma\) data vectors, covariance ingredients, tomography choices, and LSST DESC forecasting workflows.
The primary observable modelled by DSF is the excess surface density, defined as
where \(\Sigma(R)\) is the projected surface mass density, \(\overline{\Sigma}(<R)\) is the mean projected surface density enclosed within projected radius \(R\), \(\Sigma_{\rm crit}\) is the critical surface density, and \(\gamma_t(R)\) is the tangential shear [MHS+05].
The package is currently in early development. Interfaces, examples, and recommended workflows may change as the codebase is expanded and validated.
What DSF does¶
DSF is designed to connect the main ingredients needed for \(\Delta\Sigma\) forecasting:
tomographic lens and source samples,
\(\Delta\Sigma\) data-vector modelling,
galaxy-matter covariance construction,
forecast-ready inputs for Fisher or DALI analyses.
The intended workflow is:
tomography → data vector → covariance → forecast inputs
In practice, this means DSF helps users build matched lens-source bin combinations, compute stacked \(\Delta\Sigma\) observables, construct covariance ingredients, and prepare forecast inputs for downstream inference or forecasting tools.
Where to go next¶
The API reference documents the main DSF modules currently available. More installation notes and worked examples will be added as the package matures.
Documentation
References¶
R. Mandelbaum, C. M. Hirata, U. Seljak, J. Guzik, N. Padmanabhan, C. Blake, M. R. Blanton, R. Lupton, and J. Brinkmann. Systematic errors in weak lensing: application to sdss galaxy-galaxy weak lensing. Monthly Notices of the Royal Astronomical Society, 361(4):1287–1322, August 2005. URL: http://dx.doi.org/10.1111/j.1365-2966.2005.09282.x, doi:10.1111/j.1365-2966.2005.09282.x.