dorian-astro 1.0.0

Code to generate full-sky ray-traced weak gravitational lensing maps from cosmological simulations.

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Deflection Of Rays In Astrophysical Numerical simulations

Dorian is a Python package to compute full-sky ray-traced weak gravitational lensing maps starting from cosmological simulations.

For technical details, see the related paper.

Installation

The package can be installed with:

pip install dorian-astro

You will need the following dependencies:

• numpy
• scipy
• healpy
• h5py
• ducc0
• scikit-learn

News

The newest version (1.0.0) features:

• function for obtaining the observed positions of galaxies given their true position and the rays position (image_search/search_galaxy_images)
• function to convert snapshot to massmap (gadget/snapshot_to_massmap)
• function for projecting the 3D inertia tensor on the celestial sphere (geometry/project_tensor_on_cel_sphere)
• faster peak/minima finder for HEALPix maps (peaks/find_peaks_fullsky)
• minor fixes

Usage

Using the code to perform a weak lensing simulation is as simple as calling the raytrace function. For instructions see the example notebook and the template script.

The code needs you to point to the simDir folder, where all the mass shells are arranged in the Gadget-4 format (based on hdf5) and directory structure, e.g.:

simDir
 |-mapsdir_001
 | |-maps_001.0.hdf5
 | |-maps_001.1.hdf5
 | `-maps_001.2.hdf5
 |-mapsdir_002
 | |-maps_002.0.hdf5
 | |-maps_002.1.hdf5
 | `-maps_002.2.hdf5
 `-mapsdir_003
   |-maps_003.0.hdf5
   |-maps_003.1.hdf5
   `-maps_003.2.hdf5

Where each mapsdir refers to a single mass-shell, and each mass-shell can be divided into multiple files (three in the example above). Note that the code supports mass-shells with variable thickness.

If your mass-shells are in another format (e.g. HEALPix maps stored into numpy arrays), you can use the write_massmap function to convert each of them in the compatible format.

Examples

• Notebook: performing a weak lensing simulation and computing the convergence power spectrum.
• Script: performing a weak lensing simulation.

Authors

This package has been developed by Fulvio Ferlito, with contributions from: Christopher Davies, Alessandro Greco, Martin Reinecke and Volker Springel.

Contact

If you have any question, suggestion, or need help with the code, don't hesitate to contact the author.

Citation

If you use this code for you work, please cite the related paper.