johannesulf / dsigma

A Galaxy-Galaxy Lensing Python Package

dsigma is an easy-to-use python package for measuring gravitational galaxy-galaxy lensing. Using a lensing catalog, it estimates excess surface density around a population of lenses, such as galaxies in the Sloan Digital Sky Survey or the Baryon Oscillation Spectroscopic Survey. It has a broadly applicable API and can utilize data from the Dark Energy Survey (DES), the Kilo-Degree Survey (KiDS), and the Hyper-Suprime Cam (HSC) lensing surveys, among others. With core computations written in C, dsigma is very fast. Additionally, dsigma provides out-of-the-box support for estimating covariances with jackknife resampling and calculating various summary statistics. Below is a plot showing the excess surface density around galaxies in the CMASS sample calculated with dsigma.

Authors

• Johannes Lange
• Song Huang

Documentation

Documentation for dsigma with concept introductions, examples, and API documentation is available on readthedocs.

Attribution

dsigma is listed in the Astronomy Source Code Library. If you find the code useful in your research, please cite Lange & Huang (2022).

License

dsigma is licensed under the MIT License.

dsigma's Issues

dsigma output units and "little h"

Hello,

I am using dsigma and am unsure about the units for the output since it does not seem to be written explicitly in the documentation. Does the units of the output table column 'ds', the excess surface density, include the dimensionless Hubble parameter 'little h'? (i.e. is the output in units of $M_{\odot}/pc^2$ or in units of $hM_{\odot}/pc^2$?)

Thank you very much for your help,

Jordan Ducatel