romanisim: an image simulator for Roman

romanisim is a Galsim-based simulator of imaging data from the Wide Field Instrument (WFI) on the Nancy Grace Roman Space Telescope (pronounced roman-eye-sim, stylized Roman I-Sim). It uses Galsim to render astronomical scenes, WebbPSF to model the point spread function, and CRDS to access the calibration information needed to produce realistic WFI images.

The simulator starts by producing an idealized scene with Galsim and a PSF, and then proceeds to simulate the various noise sources and instrumental systematics imprinted by the system. One major feature is a fairly faithful implementation of up-the-ramp sampling and ramp-fitting, so that romanisim can produce realistic L1 images ("raw" sets of up the ramp samples like those that will be delivered from the telescope) and L2 images (calibrated images of astronomical flux per pixel).

Warning romanisim is under active developement. Its output has not been formally validated; only limited testing has been performed. For this reason, use of romanisim for preparation of ROSES proposals is not advised. Other packages like galsim's roman package or STIPS may better serve such purposes.

Documentation

See the full romanisim documentation at readthedocs.

Installation

pip install romanisim

should do most of what you want. Then

romanisim-make-image out.asdf

will render a test image. See the documentation for more information about simulating scenes you're actually interested in!

Contributing

romanisim is intended to support the community in understanding and analyzing imaging from Roman. If there are features you want to use or see, file an issue, or better yet, make a pull request!