This page provides SPHEREx spectral calibration products derived from laboratory measurements. The calibration products are delivered at four spectral granularities of 17, 34, 51, and 68 sub-channels per detector. The products include normalized spectral response functions, also referred to here as transmission curves.

The spectral calibration products are provided as a tar file. The package includes separate subdirectories for each product type:

• ChannelMaps/ contains FITS files describing the spectral-channel assignments for each detector.
• MiddlePixel/ and MeanAllPixel/ contain CSV files with the spectral response functions organized by sub-channel resolution (SubChannel17, 34, 51, or 68) and detector band (Band1-Band6).
• FidSecSummary/ provides per-channel summary CSV files including the central wavelength of each channel.
• ParameterFiles/ contains FITS maps of band-center and band-width parameters.

See the detailed spectral calibration documentation for additional information about the calibration products, channel definitions, and file organization. A brief summary of the transmission curves is provided below. Note that these files are provided in detector coordinates and therefore are flipped in the x-axis - compare to the on-sky images for detectors 4, 5 and 6.

Transmission Curves

While the transmission was measured for all pixels in lab testing, the products available here include averaged transmission curves in nominal SPHEREx channels, at four channel resolutions, derived from the per-pixel measurements.

For each spectral channel, two representative normalized spectral response functions, or transmission curves, are provided:

• Middle-pixel response (Cent): Represents the average transmission of pixels landing at the (spectral) center of the channel.
• All-pixel response (Allpix): Represents the average of the measured transmissions of all pixels belonging to the channel.

The appropriate response depends on the analysis. The middle-pixel response is generally more representative of an individual measurement. The all-pixel response may be more appropriate when measurements obtained at different positions within a spectral channel are themselves combined or averaged. For example, if multiple measurements of a deep-field source within a channel are averaged into a single measurement, the corresponding individual transmission curves sample slightly different central wavelengths; the all-pixel response provides a similarly averaged representation of the channel response.

Related Pipeline Calibration Products

These spectral calibration products are provided primarily for users who want direct access to the underlying laboratory-derived calibration measurements. Most are not calibration products used directly by the SPHEREx data-processing pipeline.

Calibration products used by the SPHEREx processing pipeline are available separately at IRSA: SPHEREx pipeline calibration products.