Preliminary updates to the NIRCam photometric calibration

Reposted from https://github.com/gbrammer/grizli/pull/107 to make a more permanent reference. As of late August 2022, a number of groups have found that there still seem to be large corrections to the individual NIRCam SCA photometric calibration required, even after the CRDS updates in late July. There is a series of ongoing calibration programs that will establish the absolute calibration of all of the modes at high precision. For now, however, those calibration data are incomplete. I have derived some corrections to the jwst_0942.pmap context using the following: The flux calibration standard J1743045 suggests that the absolute NIRISS calibration is quite good, with just a correction of 1/1.04 required for F200W The flux standard also suggests that NIRCam LW broadbands are fairly well calibrated, perhaps with the exception of a 1/0.912 correction needed for F444W The flux standard data are currently only available for the B module in some filters. To calibrate the A module and also the additional broadband SW filters, I derived relative corrections using the wealth of data taken of the LMC astrometric calibration field, where certain patches of the field have been observed by more than one NIRCam SCA. The corrections are derived by measuring photometry in the NIRISS broad bands and then calculating scale factors of all of the NIRCam SW SCAs relative to these. Relative A/B corrections for the NIRCam LW broad-band filters are also derived from the LMC data. The tabulated values in grizli/data/photom_correction.yml are the median ratios of the derived flux densities in the indicated filters to some reference, either relative or absolute. To apply the corrections relative to exposures calibrated with the current CRDS_CONTEXT, the values should be divided from the SCI and ERR arrays, which is now implemented in utils.drizzle_from_visit. The LMC mosaics are available at https://s3.amazonaws.com/grizli-v2/JwstMosaics/lmc-astrometric-field/lmc.html. The full notebook used to derive the LMC corrections is at https://s3.amazonaws.com/grizli-v2/JwstMosaics/lmc-astrometric-field/astrometric-field-photometry.ipynb. This release includes a table (summary_0989.txt) of my photometric calibration determinations and comparisons of these to the CRDS references. An official update from the NIRCam team is now available in the JWST CRDS system in jwst_0989.pmap. Please cite this DOI if you use the "v4" mosaics of JWST imaging fields produced by G. Brammer. # det filt pupil mjsr_0942 gbr ila mjsr_gbr file gbr_inv mjsr_0989 file_0989 ratio_989_gbr
# mjsr_0942 : PHOTMJSR from jwst_0942.pmap
# gbr : multiplicative corrections from G. Brammer
# ila : multiplicative corrections from I. Labbe
# mjsr_gbr = gbr * mjsr_0942
# 0942 numbers from jwst_nircam_photom_0[file].fits
# mjsr_0989 : PHOTMJSR from jwst_0989.pmap
# 0989 numbers from jwst_nircam_photom_0[file_0989].fits
# ratio_989_gbr = mjsr_0989 / mjsr_gbr
NRCA1 F090W CLEAR 3.762 0.826 --- 3.108 106 1.210 2.996 116 0.964
NRCA1 F115W CLEAR 3.299 0.914 0.876 3.014 106 1.094 2.963 116 0.983
NRCA1 F150W CLEAR 2.460 0.936 0.895 2.303 106 1.068 2.251 116 0.978
NRCA1 F200W CLEAR 2.211 0.865 0.846 1.913 106 1.155 1.892 116 0.989
NRCA2 F090W CLEAR 3.872 0.833 --- 3.224 100 1.201 3.282 110 1.018
NRCA2 F115W CLEAR 3.395 0.908 0.867 3.084 100 1.101 3.101 110 1.006
NRCA2 F150W CLEAR 2.531 0.937 0.894 2.371 100 1.067 2.384 110 1.005
NRCA2 F200W CLEAR 2.275 0.889 0.857 2.023 100 1.125 2.081 110 1.029
NRCA3 F090W CLEAR 4.026 0.762 --- 3.066 102 1.313 2.954 112 0.963
NRCA3 F115W CLEAR 3.531 0.862 0.840 3.044 102 1.160 2.949 112 0.969
NRCA3 F150W CLEAR 2.632 0.878 0.852 2.310 102 1.139 2.204 112 0.954
NRCA3 F200W CLEAR 2.366 0.800 0.794 1.892 102 1.251 1.828 112 0.966
NRCA4 F090W CLEAR 3.839 0.753 --- 2.891 105 1.328 2.910 115 1.007
NRCA4 F115W CLEAR 3.366 0.813 0.784 2.738 105 1.229 2.776 115 1.014
NRCA4 F150W CLEAR 2.509 0.837 0.811 2.100 105 1.195 2.102 115 1.001
NRCA4 F200W CLEAR 2.256 0.791 0.778 1.785 105 1.264 1.805 115 1.012
NRCB1 F090W CLEAR 3.874 0.894 --- 3.463 108 1.119 3.564 118 1.029
NRCB1 F115W CLEAR 3.397 0.959 0.897 3.258 108 1.043 3.272 118 1.004
NRCB1 F150W CLEAR 2.532 0.946 0.906 2.394 108 1.058 2.412 118 1.008
NRCB1 F200W CLEAR 2.276 0.873 0.866 1.987 108 1.145 2.022 118 1.018
NRCB2 F090W CLEAR 4.009 0.842 --- 3.377 107 1.187 3.427 117 1.015
NRCB2 F115W CLEAR 3.515 0.897 0.870 3.154 107 1.114 3.128 117 0.992
NRCB2 F150W CLEAR 2.621 0.896 0.879 2.348 107 1.117 2.305 117 0.982
NRCB2 F200W CLEAR 2.356 0.829 0.847 1.953 107 1.206 1.952 117 0.999
NRCB3 F090W CLEAR 3.706 0.914 --- 3.386 103 1.095 3.425 113 1.012
NRCB3 F115W CLEAR 3.250 0.995 0.933 3.234 103 1.005 3.186 113 0.985
NRCB3 F150W CLEAR 2.423 0.986 0.936 2.388 103 1.015 2.352 113 0.985
NRCB3 F200W CLEAR 2.178 0.901 0.888 1.963 103 1.110 1.957 113 0.997
NRCB4 F090W CLEAR 3.769 0.818 --- 3.085 099 1.222 3.043 109 0.987
NRCB4 F115W CLEAR 3.305 0.831 0.811 2.746 099 1.204 2.698 109 0.983
NRCB4 F150W CLEAR 2.464 0.849 0.822 2.092 099 1.178 2.029 109 0.970
NRCB4 F200W CLEAR 2.215 0.812 0.795 1.799 099 1.231 1.771 109 0.985
NRCBLONG F277W CLEAR 0.422 1.000 --- 0.422 104 1.000 0.417 114 0.989
NRCALONG F277W CLEAR 0.433 1.107 --- 0.480 101 0.903 0.491 111 1.024
NRCBLONG F300M CLEAR 0.952 1.000 --- 0.952 104 1.000 0.949 114 0.997
NRCALONG F300M CLEAR 0.977 1.059 --- 1.035 101 0.944 1.013 111 0.979
NRCBLONG F356W CLEAR 0.372 1.000 --- 0.372 104 1.000 0.376 114 1.011
NRCALONG F356W CLEAR 0.381 1.088 --- 0.415 101 0.919 0.405 111 0.976
NRCBLONG F410M CLEAR 0.811 1.042 1.031 0.845 104 0.960 0.875 114 1.036
NRCALONG F410M CLEAR 0.832 1.031 1.031 0.858 101 0.970 0.870 111 1.015
NRCBLONG F444W CLEAR 0.335 1.096 1.031 0.367 104 0.912 0.373 114 1.015
NRCALONG F444W CLEAR 0.343 1.136 1.031 0.390 101 0.880 0.393 111 1.007
#
# These are in 0989 but not in my own analysis
NRCA1 F140M CLEAR 5.380 1.000 --- 5.380 106 1.000 5.075 116 0.943
NRCA1 F182M CLEAR 3.788 1.000 --- 3.788 106 1.000 3.490 116 0.921
NRCA1 F210M CLEAR 4.678 1.000 --- 4.678 106 1.000 4.404 116 0.941
NRCA1 F150W2 F162M 5.106 1.000 --- 5.106 106 1.000 4.663 116 0.913
NRCA2 F140M CLEAR 5.537 1.000 --- 5.537 100 1.000 5.355 110 0.967
NRCA2 F182M CLEAR 3.898 1.000 --- 3.898 100 1.000 3.779 110 0.970
NRCA2 F210M CLEAR 4.814 1.000 --- 4.814 100 1.000 4.841 110 1.006
NRCA2 F150W2 F162M 5.255 1.000 --- 5.255 100 1.000 5.007 110 0.953
NRCA3 F140M CLEAR 5.758 1.000 --- 5.758 102 1.000 5.011 112 0.870
NRCA3 F182M CLEAR 4.053 1.000 --- 4.053 102 1.000 3.375 112 0.833
NRCA3 F210M CLEAR 5.006 1.000 --- 5.006 102 1.000 4.235 112 0.846
NRCA3 F150W2 F162M 5.464 1.000 --- 5.464 102 1.000 4.516 112 0.827
NRCA4 F140M CLEAR 5.489 1.000 --- 5.489 105 1.000 4.714 115 0.859
NRCA4 F182M CLEAR 3.864 1.000 --- 3.864 105 1.000 3.328 115 0.861
NRCA4 F210M CLEAR 4.773 1.000 --- 4.773 105 1.000 4.223 115 0.885
NRCA4 F150W2 F162M 5.210 1.000 --- 5.210 105 1.000 4.371 115 0.839
NRCB1 F140M CLEAR 5.539 1.000 --- 5.539 108 1.000 5.441 118 0.982
NRCB1 F182M CLEAR 3.900 1.000 --- 3.900 108 1.000 3.776 118 0.968
NRCB1 F210M CLEAR 4.816 1.000 --- 4.816 108 1.000 4.760 118 0.988
NRCB1 F150W2 F162M 5.257 1.000 --- 5.257 108 1.000 5.068 118 0.964
NRCB2 F140M CLEAR 5.733 1.000 --- 5.733 107 1.000 5.196 117 0.906
NRCB2 F182M CLEAR 4.036 1.000 --- 4.036 107 1.000 3.592 117 0.890
NRCB2 F210M CLEAR 4.984 1.000 --- 4.984 107 1.000 4.517 117 0.906
NRCB2 F150W2 F162M 5.440 1.000 --- 5.440 107 1.000 4.804 117 0.883
NRCB3 F140M CLEAR 5.300 1.000 --- 5.300 103 1.000 5.324 113 1.005
NRCB3 F182M CLEAR 3.731 1.000 --- 3.731 103 1.000 3.627 113 0.972
NRCB3 F210M CLEAR 4.608 1.000 --- 4.608 103 1.000 4.562 113 0.990
NRCB3 F150W2 F162M 5.029 1.000 --- 5.029 103 1.000 4.891 113 0.973
NRCB4 F140M CLEAR 5.390 1.000 --- 5.390 099 1.000 4.557 109 0.846
NRCB4 F182M CLEAR 3.794 1.000 --- 3.794 099 1.000 3.268 109 0.861
NRCB4 F210M CLEAR 4.686 1.000 --- 4.686 099 1.000 4.137 109 0.883
NRCB4 F150W2 F162M 5.115 1.000 --- 5.115 099 1.000 4.269 109 0.835
NRCBLONG F250M CLEAR 1.632 1.000 --- 1.632 104 1.000 1.646 114 1.008
NRCALONG F250M CLEAR 1.673 1.000 --- 1.673 101 1.000 1.679 111 1.004
NRCBLONG F335M CLEAR 0.851 1.000 --- 0.851 104 1.000 0.851 114 1.000
NRCALONG F335M CLEAR 0.873 1.000 --- 0.873 101 1.000 0.989 111 1.133
NRCBLONG F360M CLEAR 0.870 1.000 --- 0.870 104 1.000 0.878 114 1.009
NRCALONG F360M CLEAR 0.892 1.000 --- 0.892 101 1.000 0.929 111 1.041