  A primary goal of direct imaging techniques is to spectrally characterize the
atmospheres of planets around other stars at extremely high contrast levels. To
achieve this goal, coronagraphic instruments have favored integral field
spectrographs (IFS) as the science cameras to disperse the entire search area
at once and obtain spectra at each location, since the planet position is not
known a priori. These spectrographs are useful against confusion from speckles
and background objects, and can also help in the speckle subtraction and
wavefront control stages of the coronagraphic observation. We present a
software package, the Coronagraph and Rapid Imaging Spectrograph in Python
(crispy) to simulate the IFS of the WFIRST Coronagraph Instrument (CGI). The
software propagates input science cubes using spatially and spectrally resolved
coronagraphic focal plane cubes, transforms them into IFS detector maps and
ultimately reconstructs the spatio-spectral input scene as a 3D datacube.
Simulated IFS cubes can be used to test data extraction techniques, refine
sensitivity analyses and carry out design trade studies of the flight CGI-IFS
instrument. crispy is a publicly available Python package and can be adapted to
other IFS designs.
