1.1. For Pandeia Engine v4.0 & v2024.12

Python Requirements:

Installing the Pandeia Engine requires a python environment with the dependencies listed above, a set of telescope-specific datafiles, and an optional (but highly recommended) second set of data files for additional spectral manipulation capabilities.

2. Code

The engine can be installed with

pip install pandeia.engine==4.0

or for Roman:

pip install pandeia.engine==2024.12

Then set up the data files.

3. Data

3.1. Required Data

In order to function, the Pandeia Engine requires one set of reference data (containing instrument definitions):

• James Webb Space Telescope: https://stsci.app.box.com/v/pandeia-refdata-v4p0-jwst (4 GiB)
• Nancy Grace Roman Space Telescope: https://stsci.box.com/v/pandeia-data-v2024p12-roman (407 MiB)

Download and untar the files to a suitable location.

Environment variable: $pandeia_refdata must point to the location of the top of the data file tree (the directory containing the VERSION_PSF file)

• The base Synphot reference atlas. The Synphot reference atlases (https://archive.stsci.edu/hlsp/reference-atlases) are used to provide more spectroscopic functionality.

  • Only Synphot 1 (normalization bandpasses, HST bandpasses) is required: https://archive.stsci.edu/hlsps/reference-atlases/hlsp_reference-atlases_hst_multi_everything_multi_v16_sed.tar

Once untarred, the files will produce a directory tree of grp/redcat/trds. The pandeia.engine uses the contents of the trds directory.

3.2. Recommended Data

The rest of the Synphot datasets are optional and enable specific classes of template spectra.

• Synphot 2 (Stellar and Galactic Model Files - brown2014, pickles, bz77)
• Synphot 3 (Castelli & Kurucz 2004 Atlas  - ck04models)
• Synphot 4 (Kurucz 1993 Atlas - k93models)
• Synphot 5 (Phoenix models - phoenix)
• Synphot 7 (JWST ETC Spectra - atmo2020, brown2019, comp_qso, swire, novae, stellar_pop, solsys, pne)

Once untarred, the files will produce a directory tree of grp/redcat/trds. The pandeia.engine uses the contents of the trds directory.

Environment variable: $PYSYN_CDBS must point to the trds directory (NOT grp)

4. Verify Installation

Open up a terminal with access to the conda installation, and type

python -c "import pandeia.engine; pandeia.engine.pandeia_version()"

If properly installed and configured, it should show the refdata version and synphot data directory, like this:

Pandeia Engine version:  4.0
Pandeia RefData version:  4.0
Pysynphot Data:  /your/data/directory/synphot

or for Roman:

Pandeia Engine version:  2024.12
Pandeia RefData version:  2024.12
Pysynphot Data:  /your/data/directory/synphot

5. Helper Script

The following script (which can also be added to your .bashrc or .bash_profile file) assumes you are operating in a BASH shell where a python installation has been installed and activated, that you've installed the pandeia refdata in ${HOME}/data/pandeia, and the cdbs folder from the additional dataset moved and renamed to ${HOME}/data/synphot

#!/bin/sh
export PYSYN_CDBS=${HOME}/data/synphot
export pandeia_refdata=${HOME}/data/pandeia

Once in place, "source"ing this file will set up the pandeia environment.