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### Simulated NIRCam imaging and reduction for CEERS Pointing 5 ###
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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 (see below).


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## Summary

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)


Contact: Micaela Bagley (mbagley@utexas.edu)


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## Changes from SDR1

- Updated photometry: these simulated NIRCam images use an updated 
  version of the Santa Cruz SAM mock catalog that includes the effects 
  of ISM dust extinction.

- Full depth in F115W and F356W: we have included the additional imaging 
  in F115W taken as the SWC counterpart to the NIRCam WFSS observations in 
  this field, as well as a small number of additional F356W images obtained 
  as direct images for the WFSS observations.

- Images are now pixel-aligned across all filters, and on a pixel scale 
  of 30mas


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## Notes on Header Keywords

The photometry information in the headers produced by the development
version of the Calibration Pipeline was incorrect for the pixel scale 
of the mosaics. Specifically, the header keywords 'PIXAR_SR' and 
'PIXAR_A2' maintained the values corresponding to the original pixel 
scales in the short and long wavelength channels, rather than those 
appropriate for 0.03"/pixel. (If you are using jwst datamodels, these 
keywords are model.meta.photometry.pixelarea_steradians and
model.meta.photometry.pixelarea_arcsecsq. 

We have manually updated these values to reflect the 0.03"/pixel scale. 
Please use these new values when measuring photometry. We urge 
caution in using 'PHOTMJSR' (model.meta.photometry.conversion_megajanskys)
and 'PHOTUJA2' (model.meta.photometry.conversion_microjanskys), as we have 
not confirmed these values. Additionally, the keyword 'PXSCLRT' in 
the primary header is also incorrect (it currently states a pixel scale 
ratio of 1.0 relative to each input detector scale). 


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## Directory Contents

We include the mosaics output by Stage 3 of the JWST Calibration Pipeline
as well as individual extensions of the mosaic files that are smaller and 
therefore may be easier to use.

The mosaic in each filter is called ceers5_[filt]_i2d.fits.gz, where [filt]
is f115w, f150w, f200w, f277w, f356w, or f444w. These images are saved as 
multi-extension fits files, each of which is ~1 GB and unzips to ~1.4 GB.

For information on i2d data products: https://jwst-pipeline.readthedocs.io/en/latest/jwst/data_products/science_products.html#resampled-2-d-data-i2d-and-s2d 

We have also separated individual extensions (maintaining the JWST data model 
structure and additional metadata), and saved them as:
  - ceers5_[filt]_sci.fits.gz
  - ceers5_[filt]_wht.fits.gz
  - ceers5_[filt]_err.fits.gz
These individual extensions are ~100-180 MB and unzip to ~200 MB.

Two versions of the F115W images are available.
  - ceers5_f115w_*: the full depth including the SWC imaging taken during 
      the WFSS observations
  - ceers5_f115w_partial_*: the imaging excluding the F115W exposures from
      the WFSS observations