Simulated NIRCam Wide Field Slitless Spectroscopy for CEERS Pointings 5-8

We have simulated NIRCam WFSS observations and the associated imaging for all four CEERS pointings (CEERS 5-8) using MIRAGE version 2.2.1, with input sources taken from a mock catalog created using the Santa Cruz semi-analytic model for galaxy evolution. The images were simulated using pointing and XML files based on the CEERS APT. NIRCam WFSS exposures in each grism are taken with one LWC direct image followed by two LWC out-of-field images to identify the sources associated with the spectra. During all CEERS WFSS observations and LWC imaging, the SWC observes with F115W to add depth to the NIRCam imaging in these fields.

To access the full data release directly, visit this link. Please see the associated README describing the release.

Alternatively, see below to access the input models, raw data, calibrated count rate images, and extracted spectra.


  • Instrument: NIRCam
  • Mode: WFSS
  • Source of Simulations: MIRAGE v2.2.1, grismconf V3
  • Calibration Pipeline Used: jwst v1.4.2
  • APT: CEERS ERS 1345
  • Target: CEERS Pointings 5-8 (as primary with MIRI parallels)
  • Filters: SWC F115W; LWC F356W, GRISMR, GRISMC
  • Readout: SHALLOW4
  • Observation specification: 6 groups, 1 integration
  • Dithers: 4 point dither in each filter, defined with the MIRI parallels; direct and out-of-field imaging with each set of grism exposures


Catalogs - Input catalogs and spectra

Dispersed seed images - the input seed images, i.e., noiseless simulated data

Datacubes containing all of the individual simulated sources

All of the Mirage raw output (including direct imaging), which can be run through the JWST Calibration Pipeline

Data in DN/s (including direct imaging), these have been run through Stage 1 and WCS assignment of the Calibration Pipeline. They can be used to extract spectra in the "classic" way. Note that flat fields have not been applied to these files.

Extracted spectra using a mock, idealized extraction. See the README for information on the extraction and reading in the extracted spectra.


  • These spectra were generated using NIRCam grismconf V3 reference files and should therefore be extracted using this version. They will have different shapes and offsets than the real data.
  • We expect the continuum to be detected in these spectra with a SN~2 for ~22 mag sources. There are many fainter sources in the input catalog, and therefore many extracted spectra with emission lines only.

Simulated NIRCam Imaging Mosaics of a Single Pointing

Here we provide an updated set of NIRCam imaging mosaics covering a single CEERS pointing (CEERS 5). This is the same CEERS pointing that was released as part of SDR1, but with three updates/improvements:

  • The images were simulated with updated photometry from the Santa Cruz SAM mock catalog that now includes dust. The updated input catalog is available here.
  • We've included additional imaging in F115W that will be taken as the SWC counterpart to the NIRCam WFSS observations in this field. We've also included a small number of additional F356W images that will be obtained as direct and out-of-field images for the WFSS observations.
  • The images are now pixel-aligned across all filters.

Please see the associated README describing the release. These simulated images are also presented in Bagley et al. (2023).

To access the full data release directly, visit this link. Alternatively, see below to access the fully reduced mosaics in each filter.


  • Instrument: NIRCam
  • Mode: Imaging
  • Source of Simulations: MIRAGE v2.2.1
  • Calibration Pipeline Used: jwst v1.4.7a1.dev23 (a development version)
  • CRDS Context: 0791
  • APT (version 2021.2): CEERS ERS 1345
  • Target: CEERS Pointing 5 (in parallel with prime NIRSpec MSA), with additional depth in F115W and F356W obtained as part of the NIRCam WFSS observations in this field
  • Filters: SWC F115W, F150W, F200W; LWC F277W, F356W, F444W
  • Readout: MEDIUM8 (NIRSpec parallel); SHALLOW4 (WFSS imaging)
  • Observation specification: 9 groups, 1 integration (NIRSpec parallel); 6 groups, 1 integration (WFSS imaging)
  • Dithers: 3 dithers, steps specified by NIRSpec nods (NIRSpec parallel); 4 dithers, steps specified by MIRI parallel, with direct images and out of field imaging (WFSS imaging)


  • Fully reduced mosaics in all 6 filters for a single CEERS pointing are available here or in the table below. Please see the associated README.
  • The mosaics are on pixel scales of 0.03"/pix and are pixel aligned across all filters.
  • We have gzipped all files to save on space. The full images, called 'i2d', are ~1 GB and unzip to ~1.4 GB. We have also separated individual extensions (maintaining the JWST data model structure and additional metadata), each of which is ~100-180 MB and unzips to ~200 MB.
  • Two versions of the F115W images are available: the full depth mosaic including the SWC imaging taken during the WFSS observations (ceers5_f115w_*), and the imaging excluding the F115W exposures from the WFSS observations (ceers5_f115w_partial_*)

Mock Galaxy Catalog

The main input for our simulated NIRCam images is a mock galaxy catalog created with the Santa Cruz Semi-Analytic Model (SAM). This catalog covers a field of 782 sq. arcmin, overlapping with the observed EGS field and spanning z ~ 0 to 10. The mock catalog is presented in Yung et al. (2022). The physical model is configured identically as the model presented in Somerville et al. (2021).

Download the CEERS SAM mock galaxy catalog:

  • FITS table (~750 MB)
  • ASCII table (1.1 GB)
  • Please note that this version of the SAM catalog DOES include extinction by dust. This version is an update to that presented in SDR1 and was used to create the SDR3 NIRCam Imaging Mosaics, and so is appropriate to use in comparison with these simulated products.

Please see the associated README describing the catalog, columns, and the references related to the creation of the SAM.

Additional Inputs - high-redshift Galaxies and Point sources

We have also added the seven z~9 galaxies in the EGS field presented by Finkelstein et al. (2022) to the imaging and WFSS simulations. The JWST photometry is estimated using the best-fit EAZY template for each source's Hubble and Spitzer photometry. Download the catalog of z~9 source positions and photometry:

Finally, we have included point sources in the NIRCam imaging and WFSS simulations. The positions and magnitudes of bright (V<16) point sources in the EGS field are added from 2MASS, WISE and Gaia. We added fainter point sources (16 < V < 29) using the Besançon Model to approximate the correct stellar density and luminosity distribution in the EGS field. Download the catalog of point sources:

Note: the point source catalog is in Vega magnitudes, while all other input catalogs are in AB magnitudes.