J-UBIK

The JAX-accelerated Universal Bayesian Imaging Kit is a python package for high-fidelity Bayesian imaging.

J-UBIK allows to image observations from different instruments with Bayesian posterior uncertainties and component separation. Next to many useful generic tools and building blocks, JUBIK comes with a series of sky models and instrument implementations, namely:

• Chandra
• eROSITA
• James Webb Space Telescope

Installation

This package can be installed via pip.

git clone https://github.com/NIFTy-PPL/J-UBIK
cd j-ubik
pip install --user .

for a regular installation. For editable installation add the -e flag.

Requirements

• JAX
• astropy
• NIFTy (follow installation for NIFTy.re, the JAX implementation of NIFTy)
• ducc0
• matplotlib

Testing

For testing you need pytest to be installed. To run the tests execute the following from the j-ubik directory:

bash pytest-3 test/

Tests considering Chandra are skipped if ciao is not installed.

Contributing

Guidelines for contribuation can be found in CONTRIBUTING.md

Instrument specific Requirements

• Chandra
• eROSITA
• James Webb Space Telescope

Additional Files

Additional calibration files might be needed for instrument-specific pipelines.

Chandra

J-UBIK allows to process observations from Chandra x-ray observatory.

Requirements

• ciao >= 4.16
• marx

We recommend installation of both via conda / conda-forge ciao & marx

eROSITA

J-UBIK allows to process and image event files from the eROSITA x-ray observatory.

Requirements

To process eROSITA observations or produce realistic synthetic data, you will need: - eSASS, the eROSITA Science Analysis Software System. In particular, the current version of J-UBIK only supports using eSASS through the official docker container to ensure cross-compatibility. - caldb folder, this allows to compute the eROSITA response accurately. Either the caldb from data release 1 (DR1) or from the early data release (EDR) should be present inside the data/ directory. This folder can be downloaded at caldb download. - Download the data if you want to work with public eROSITA data, see edr and dr1.

Demo

In the demo/ repository, erosita_inference.py allows to run a generic image reconstruction with real and synthetic (mock) eROSITA data. In order to run a mock demo, you will need to download both the calibration folder as specified in the Requirements section and an actual observation, in order to build realistic exposure maps. A good example is LMC_dataset. For more information on how to run erosita_demo.py see the corresponding docstring.

James Webb Space Telescope

J-UBIK allows to process and image event files from the James Webb Space Telescope.

Requirements

In order to make use of the JWST capabilities of the package, you will need to: - Install the jwst package. - Install stpsf. - Install gwcs.

For more details see jwst_demo.py in the demo/ repository. Alternatively, you can install these requirements via bash pip install --user .[jwst]

NOTE: - Importing jubik sets the floating point precision in jax to float64. - WebbPSF has shown some compatibility issues with the numexpr package.
The current version of the code has been tested successfully on numexpr version==2.8.4.