• "cube/cube_reconstructed.fits" - a cube of the signal plus Gaussian noise, in units of e^–/s
• "cube/cube_reconstructed_signal.fits" - a cube of the signal, in e^–/s
• "cube/cube_reconstructed_noise.fits" - a cube of the noise (including all noise sources), in e^–/s
• "cube/cube_reconstructed_snr.fits" - the signal cube divided by the noise cube
• "cube/cube_reconstructed_saturation.fits" - 3-D saturation map, where 1 = partially saturated, and 2 = fully saturated

These files represent the scene as reconstructed from the "observation." All files have a single header containing a 3-D array with the axes in order wavelength, x, and y. All information for reconstituting the coordinates and wavelengths is given in the single header. Note that the header defines, per limitations of the FITS standard, a linear wavelength scale. For NIRSpec IFU in particular, the actual wavelength scale is not linear; see "lineplot/lineplots_wave_pix.fits" for the actual wavelength scale in this case.

There will also be files in the "model" directory, which will be empty except for IFU modes.

• cube/model/cube_flux_n.fits
• cube/model/cube_flux_plus_background_n.fits

These files are equivalent in format and content to the "cube/cube_flux.fits" and "cube/cube_flux_plus_background.fits" files obtained from the other modes and described above, with the difference that each of the files is a y-axis slice through the input scene cube. Within each file, only 2 y-axis locations in the array are populated for all values of x and wavelength, corresponding to one IFU element. The rest of the cube contains zeroes.

Image

• "image/image_detector.fits" - the signal, in e^–/s
• "image/image_saturation.fits"- the SNR
• "image/image_snr.fits" - the saturation, where 1 = partially saturated and 2 = fully saturated
• "image/image_ngroups_map.fits" - a map giving the number of groups before a given pixel will saturate

These are the 2-D images displayed by the ETC. First header (hdu 0) contains a 2-D array of all of the values. As with the scene cubes, the header contains the spatial information for the scene.

There will be "unrotated" versions of each of the above images for all slit and slitless modes. These files are identical to the files listed above except for the spatial orientation of the trace.

For coronagraphic imaging, these files correspond to the chosen PSF subtraction strategy.

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Plot directories

Lineplot

All of these files have 2 FITS headers, with an array of data (and explanatory headers) in the second header (hdu 1):

• "wave_calc" - 1-D wavelengths (in μm), corresponding to the spectra (whether input from the user or from the ETC library) input into the calculation.
• "wave_pix" - 1-D wavelength (in μm), corresponding to the output of the calculation. Unless a spectroscopic mode is specified, this file will have a single record with a single entry, which is the wavelength of the requested observation.

Some of these correspond to the line plots displayed in the ETC, but many do not.

These files contain inputs to the calculated observation, and have 2 records, wavelength (equivalent to "wave_calc") and the specified value, in their second header (hdu 1):

• "target" - combined flux of all the targets in the scene re-sampled onto the calculation's input wavelength grid, in mJy (as a function of wavelength)
• "fp" - the combined flux in e^–/s incident on the detector focal plane
• "bg" - the (assumed spatially uniform) background flux input into the calculation, in MJy/sr
• "bg_rate" - the background flux input into the calculation in e^–/s

The following files are extracted from the calculated observation. The data are stored in the second header (hdu 1), and consist of 2 records: wavelength (equivalent to "wave_pix") and value. Unless a spectroscopic mode is used, the records will only have one entry—for the wavelength of the observation—in each. The values correspond to the scalar values displayed in the Reports pane of the ETC. For spectroscopic modes, full arrays are defined in the records, and the scalar value reported in the Reports pane is the value at the reference wavelength.

• "total_flux" - the total flux onto the detector extracted from the calculation, in e^–/s
• "extracted_flux_plus_bg" - the flux of the target extracted from the calculation, in e^–/s
• "extracted_flux" - the flux of the target extracted from the calculation, with background subtracted, in e^–/s
• "extracted_noise" - the extracted noise (incorporating all instrumental noise sources), in e^–/s
• "sn" - the extracted SNR (calculated as extracted_flux/extracted_noise)
• "extracted_bg_only" - the background flux extracted from the output of the calculation, in e^–/s
• "extracted_bg_total" - the background plus contamination from sources in the scene, in e^–/s
• "extracted_contamination" - just the background contamination, in e^–/s
• "n_partial_saturated" - number of partially saturated pixels in the output, as a function of wavelength
• "n_full_saturated" - number of fully saturated pixels in the output, as a function of wavelength
• "contrast" - (coronagraphic imaging only) companion-to-host flux ratio, as a function of wavelength

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Input data

"input.json" - a JSON-formatted text file containing a complete record of the inputs to the ETC. This can be used as input to the ETC when run as a scriptable standalone Python program.

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