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The Pandeia Engine is a Python module (compatible with Python 3.6 8 and later) that functions as the computational engine of the JWST ETC and Roman ETC. It can be imported and run as a standalone module.
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The Pandeia Engine API may change at any time. The following information and examples are for Pandeia Engine 12.70.x only, and are not guaranteed to be accurate or functional for previous or future releases. Updates (and information about planned pending API changes) can be found on the Pandeia Engine News page. |
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The full API documentation, with all possible options and combinations for any instrument, can be found in this filelink.
Examples
The following calculation defines a JWST NIRCam observation in SW Imaging mode using the full subarray and rapid readout pattern and f070w filter, for a flat-spectrum (in fnu) point source normalized to 0.001 mJy, intended to be observed with a 0.2" aperture. Note that it specifies a background precomputed for a specific date and celestial location; actual user-configured backgrounds are available in the JWST web ETC (and can be downloaded from there)
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{
"background": "minzodi",
"background_level": "benchmark",
"calculation": {
"effects": {
"saturation": null
},
"noise": {
"crs": null,
"ffnoisedark": null,
}
}"excess": null,
"configuration": {
"detectorffnoise": {null,
"nexpreadnoise": 1null,
"ngroupscatter": 10,null
}
"nint": 1},
"configuration": {
"readout_patterndetector": "rapid",{
"subarraynexp": "full"1,
},
"instrumentngroup": {10,
"aperturenint": "sw"1,
"disperserreadout_pattern": null"rapid",
"filtersubarray": "f070wfull",
},
"instrument": "nircam",{
"modeaperture": "sw_imaging",
}
"disperser": }null,
"scene": [
{"filter": "f070w",
"positioninstrument": {"nircam",
"orientationmode": 0.0,"sw_imaging"
}
},
"x_offsetscene": 0.0,[
{
"y_offset "position": 0.0
{
} "orientation": 0.0,
"shapex_offset": {0.0,
"geometryy_offset": "point"0.0
},
"spectrumshape": {
"extinctiongeometry": {"point"
},
" "spectrum": {
"extinction": {
"bandpass": "j",
"law": "mw_rv_31",
"unit": "mag",
"value": 0.0
},
"lines": [],
"name": "generic source",
"normalization": {
"norm_flux": 0.001,
"norm_fluxunit": "mjy",
"norm_wave": 2.0,
"norm_waveunit": "microns",
"type": "at_lambda"
},
"redshift": 0.0,
"sed": {
"sed_type": "flat",
"unit": "fnu",
"z": 0.0
}
}
}
],
"strategy": {
"aperture_size": 0.1,
"background_subtraction": true,
"display_string": "Imaging Aperture Photometry",
"method": "imagingapphot",
"sky_annulus": [
0.22,
0.4
],
"target_source": "1",
"target_type": "coords",
"target_xy": [
0.0,
0.0
],
"units": "arcsec"
}
}
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The following dictionary defines a Roman WFI Imaging observation with the F062 filter, imaging defocus_small subarray (for a 3.04s 66s read time), medium8 readout pattern, and 6 groups; for a 0.001 mJy flat-spectrum point source (in fnu) intended to be observed with a 0.2" aperture.
(click here to download as a JSON file: imaging_f062_medium8_imagingdefocus_small.jeng)
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{
"background": "minzodi",
"background_level": "benchmark",
"calculation": {
"effects": {
"backgroundsaturation": "minzodi",
null
"background_level": "benchmark" },
"calculationnoise": {
"effectscrs": {null,
"saturationdark": null,
},
"noiseexcess": {null,
"crsffnoise": null,
"ffnoisereadnoise": null,
"scatter": null
}
},
"configuration": {
"detector": {
"nexp": 1,
"ngroup": 610,
"nint": 1,
"readout_pattern": "medium8",
"subarray": "imagingdefocus_small"
},
"instrument": {
"aperture": "imaging",
"disperser": null,
"filter": "f062",
"instrument": "wfi",
"mode": "imaging"
}
},
"scene": [
{
"position": {
"orientation": 0.0,
"x_offset": 0.0,
"y_offset": 0.0
},
"shape": {
"geometry": "point"
},
"spectrum": {
"extinction": {
"bandpass": "j",
"law": "mw_rv_31",
"unit": "mag",
"value": 0.0
},
"lines": [],
"name": "generic source",
"normalization": {
"norm_flux": 0.001,
"norm_fluxunit": "mjy",
"norm_wave": 2.0,
"norm_waveunit": "microns",
"type": "at_lambda"
},
"redshift": 0.0,
"sed": {
"sed_type": "flat",
"unit": "fnu",
"z": 0.0
}
}
}
],
"strategy": {
"aperture_size": 0.2,
"background_subtraction": true,
"display_string": "Imaging Aperture Photometry",
"method": "imagingapphot",
"sky_annulus": [
0.4,
0.6
],
"target_source": "1",
"target_type": "coords",
"target_xy": [
0.0,
0.0
],
"units": "arcsec"
}
} |
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