###############################
#   NIRCam mosaics DR 0.2     #
#    COSMOS-Web Epoch 1       #
###############################

15 Aug 2023

We provide the NIRCam data reduction for the first epoch of COSMOS-Web 
(GO #1727; PIs: Kartaltepe & Casey; see Casey & Kartaltepe et al. 2023), 
consisting of six visits (out of  the total 152) corresponding to visits 
#43-48. These observations took place on 5-6 January 2023.

CRDS Context pmap: 1017
Calibration Pipeline Used: v1.8.3
Filters: F115W, F150W, F277W, F444W
Instrument: NIRCam

This directory contains the DR 0.2 version of the NIRCam mosaic data reduction.
The raw images were processed using the JWST Calibration Pipeline v1.8.3 (Bushouse et al. 2022),
which we enhanced with customized modifications and reduction techniques.

Each mosaic is present in two different resolutions: 30mas and 60mas. 
Astrometry is anchored to Gaia-EDR3 and bootstrapped from the HST/F814W imaging
(Koekemoer et al. 2007) and COSMOS2020 catalogs (Weaver et al. 2022).

The names of the files are:
mosaic_nircam_(filter.lower())_COSMOS-Web_XXmas_v0_2_i2d.fits
where XX is the resolution in mas (30 or 60).

The structure of *i2d.fits is as following:
HDU 	EXTNAME 	HDU Type 	DataType Dimensions
0     N/A 		primary	N/A   	N/A
1	SCI 		IMAGE		float32 ncols x nrows
2 	ERR		IMAGE		float32 ncols x nrows
3 	CON 		IMAGE 		int32   ncols x nrows x nplanes
4 	WHT 		IMAGE 		float32 ncols x nrows
5 	VAR_POISSON IMAGE		float32 ncols x nrows
6 	VAR_RNOISE 	IMAGE		float32 ncols x nrows
7 	VAR_FLAT 	IMAGE		float32 ncols x nrows

The definition of each of this extension is available here:
https://jwst-pipeline.readthedocs.io/en/latest/jwst/data_products/science_products.html

To facilitate the handling of these data the SCI, ERR, WHT extensions have been extracted 
and placed in the following sub-folder: extensions

Four additional images are present in this sub-folder:
mask_lw_30mas.fits
mask_sw_30mas.fits
mask_lw_60mas.fits
mask_sw_60mas.fits 
and indicate the number of integrations for each pixel in the corresponding images at the
resolution of the mosaic.

The 5σ depths in apertures of 0.15’’ radius (without any corrections) are:
# integrations  F115W 	F150W  	F277W 	F444W
# 1 (3.7%) 	26.87 	27.14	27.71	27.61
# 2 (51%)	27.13	27.35	27.99	27.83
# 3 (3.1%)	27.26	27.50	28.12	27.94
# 4 (42%)	27.45	27.66	28.28	28.17
(Computed by Louise Paquereau)

A systematic offset of ~2-6 mas is present in DEC compared to the reference image 
(COSMOS2020)

COSMOS2020 - JWST mosaics
    F444W
    RA                 DEC
    med:  -0.7 mas    med:  -2.9 mas
    mean: -0.8 mas    mean: -2.1 mas
    MAD:  11.1 mas    MAD:  11.5 mas

    F277W
    RA                 DEC
    med:  -0.4 mas    med:  -4.0 mas
    mean: -0.0 mas    mean: -3.7 mas
    MAD:  10.1 mas    MAD:  10.1 mas

    F150W
    RA                 DEC
    med:  -1.1 mas    med:  -4.7 mas
    mean: -1.4 mas    mean: -4.4 mas
    MAD:  10.4 mas    MAD:  10.1 mas

    F115W
    RA                 DEC
    med:  -1.4 mas    med:  -5.7 mas
    mean: -1.6 mas    mean: -6.1 mas
    MAD:  10.1 mas    MAD:   9.7 mas

This work was made possible by utilizing the CANDIDE cluster at the Institut d’Astrophysique
de Paris, which was funded through grants from the PNCG, CNES, DIM-ACAV, and the Cosmic Dawn
 Center and maintained by S. Rouberol.

The pipeline used for the data reduction incorporated codes from Anton M. Koekemoer,
Micaela Bagley, and Daizhong Liu

For any question or to report something, please send a message to:
maximilien.franco@austin.utexas.edu


================
## References ##
================

Bushouse, H. et al. 2022, https://ui.adsabs.harvard.edu/abs/2022zndo...7429939B
Casey, C. M., Kartaltepe, J. S. et al. 2023, ApJ, in press, https://ui.adsabs.harvard.edu/abs/2022arXiv221107865C
Koekemoer, A. M. et al. 2007, ApJS, 172, 196, https://ui.adsabs.harvard.edu/abs/2007ApJS..172..196K
Weaver, J. R. et al. 2022, ApJS, 258, 11,  https://ui.adsabs.harvard.edu/abs/2022ApJS..258...11W