Reference Files¶
The cube_build step uses CUBEPAR reference file.
CUBEPAR reference file¶
- REFTYPE
CUBEPAR
- Data models
The CUBEPAR reference file contains parameter values used to construct the output IFU cubes.
Reference Selection Keywords for CUBEPAR¶
CRDS selects appropriate CUBEPAR references based on the following keywords. CUBEPAR is not applicable for instruments not in the table.
Instrument |
Keywords |
|---|---|
MIRI |
INSTRUME, EXP_TYPE, DATE-OBS, TIME-OBS |
NIRSPEC |
INSTRUME, EXP_TYPE, OPMODE, DATE-OBS, TIME-OBS |
Standard Keywords¶
The following table lists the keywords that are required to be present in all reference files. The first column gives the FITS keyword names. The second column gives the jwst data model name for each keyword, which is useful when using data models in creating and populating a new reference file. The third column gives the equivalent meta tag in ASDF reference file headers, which is the same as the name within the data model meta tree (second column).
FITS Keyword |
Data Model Name |
ASDF meta tag |
|---|---|---|
AUTHOR |
model.meta.author |
author |
DATAMODL |
model.meta.model_type |
model_type |
DATE |
model.meta.date |
date |
DESCRIP |
model.meta.description |
description |
FILENAME |
model.meta.filename |
N/A |
INSTRUME |
model.meta.instrument.name |
instrument: {name} |
PEDIGREE |
model.meta.pedigree |
pedigree |
REFTYPE |
model.meta.reftype |
reftype |
TELESCOP |
model.meta.telescope |
telescope |
USEAFTER |
model.meta.useafter |
useafter |
NOTE: More information on standard required keywords can be found here: Standard Required Keywords
Type Specific Keywords for CUBEPAR¶
In addition to the standard reference file keywords listed above, the following keywords are required in CUBEPAR reference files, because they are used as CRDS selectors (see Reference Selection Keywords for CUBEPAR):
Keyword |
Data Model Name |
|---|---|
EXP_TYPE |
model.meta.exposure.type |
MIRI Reference File Format¶
The MIRI CUBEPAR reference files are FITS format, with 5 BINTABLE extensions. The FITS primary data array is assumed to be empty. The format and content of the MIRI CUBEPAR reference file
EXTNAME |
XTENSION |
Dimensions |
|---|---|---|
CUBEPAR |
BINTABLE |
TFIELDS = 6 |
CUBEPAR_MSM |
BINTABLE |
TFIELDS = 6 |
MULTICHANNEL_MSM |
BINTABLE |
TFIELDS = 5 |
CUBEPAR_EMSM |
BINTABLE |
TFIELDS = 5 |
MULTICHANNEL_EMSM |
BINTABLE |
TFIELDS = 4 |
MULTICHANNEL_DRIZ |
BINTABLE |
TFIELDS = 1 |
NIRSPec Reference File Format¶
The NIRSpec CUBEPAR reference files are FITS format, with 9 BINTABLE extensions.
EXTNAME |
XTENSION |
Dimensions |
|---|---|---|
CUBEPAR |
BINTABLE |
TFIELDS = 6 |
CUBEPAR_MSM |
BINTABLE |
TFIELDS = 6 |
MULTICHAN_PRISM_MSM |
BINTABLE |
TFIELDS = 5 |
MULTICHAN_MED_MSM |
BINTABLE |
TFIELDS = 5 |
MULTICHAN_HIGH_MSM |
BINTABLE |
TFIELDS = 5 |
CUBEPAR_EMSM |
BINTABLE |
TFIELDS = 5 |
MULTICHAN_PRISM_EMSM |
BINTABLE |
TFIELDS = 4 |
MULTICHAN_MED_EMSM |
BINTABLE |
TFIELDS = 4 |
MULTICHAN_HIGH_EMSM |
BINTABLE |
TFIELDS = 4 |
The formats of the individual table extensions are listed below, first for the MIRI reference file and then for NIRSpec.
Table |
Column |
Data type |
Units |
|---|---|---|---|
CUBEPAR |
CHANNEL |
shortint |
N/A |
BAND |
ch*6 |
N/A |
|
WAVEMIN |
float |
microns |
|
WAVEMAX |
float |
microns |
|
SPAXELSIZE |
float |
arcseconds |
|
SPECTRALSTEP |
double |
microns |
|
CUBEPAR_MSM |
CHANNEL |
shortint |
N/A |
BAND |
ch*6 |
N/A |
|
ROISPATIAL |
float |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
POWER |
double |
unitless |
|
SOFTRAD |
double |
unitless |
|
MULTICHANNEL_MSM |
WAVELENGTH |
double |
microns |
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
POWER |
double |
unitless |
|
SOFTRAD |
double |
unitless |
|
CUBEPAR_EMSM |
CHANNEL |
shortint |
N/A |
BAND |
ch*6 |
N/A |
|
ROISPATIAL |
float |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
SCALERAD |
double |
unitless |
|
MULTICHANNEL_EMSM |
WAVELENGTH |
double |
microns |
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
SCALERAD |
double |
unitless |
|
MULTICHANNEL_DRIZ |
WAVELENGTH |
double |
microns |
Table |
Column |
Data type |
Units |
|---|---|---|---|
CUBEPAR |
DISPERSER |
ch*5 |
N/A |
FILTER |
ch*6 |
N/A |
|
WAVEMIN |
double |
microns |
|
WAVEMAX |
double |
microns |
|
SPAXELSIZE |
double |
arcseconds |
|
SPECTRALSTEP |
double |
microns |
|
CUBEPAR_MSM |
DISPERSER |
ch*5 |
N/A |
FILTER |
ch*6 |
N/A |
|
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
POWER |
double |
unitless |
|
SOFTRAD |
double |
unitless |
|
MULTICHAN_PRISM_MSM |
WAVELENGTH |
double |
microns |
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
POWER |
double |
unitless |
|
SOFTRAD |
double |
unitless |
|
MULTICHAN_MED_MSM |
WAVELENGTH |
float |
microns |
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
POWER |
double |
unitless |
|
SOFTRAD |
double |
unitless |
|
MULTICHAN_HIGH_MSM |
WAVELENGTH |
float |
microns |
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
POWER |
double |
unitless |
|
SOFTRAD |
double |
unitless |
|
CUBEPAR_EMSM |
DISPERSER |
ch*5 |
N/A |
FILTER |
ch*6 |
N/A |
|
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
SCALERAD |
double |
unitless |
|
MULTICHAN_PRISM_EMSM |
WAVELENGTH |
double |
microns |
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
SCALERAD |
double |
unitless |
|
MULTICHAN_MED_EMSM |
WAVELENGTH |
float |
microns |
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
SCALERAD |
double |
unitless |
|
MULTICHAN_HIGH_EMSM |
WAVELENGTH |
float |
microns |
ROISPATIAL |
double |
arcseconds |
|
ROISPECTRAL |
double |
microns |
|
SCALERAD |
double |
unitless |
These reference files contain tables for each wavelength band giving the spatial and spectral size, and the size of the region of interest (ROI) to use to construct an IFU cube. If only one band is used to construct the IFU cube then the CUBEPAR and CUBEPAR_MSM or CUBE_EMSM tables are used. These types of cubes will have a linear - wavelength dimension. If more than one wavelength band is used to build the IFU cube then the MULTICHANNEL (MIRI) or MULTICHAN (NIRSPEC) tables are used o set the spectral and spatial roi size, and the wavelength dependent weighting function parameters. For multi-band IFU cubes then the final spatial size will be the smallest one from the list of input bands and these cubes will have a non-linear wavelength dimension.
The MIRI reference table descriptions:
CUBEPAR table contains the spatial and spectral cube sample size for each band.
CUBEPAR_MSM table contains the Modified Shepard Method (MSM) weighting values to use for each band.
MULTICHANNEL_MSM table is used for the MSM weighting and contains the wavelengths and associated region of interest size to use when IFU cubes are created from several bands and the final output is to have an IFU cube of varying spectral scale.
CUBEPAR_EMSM table contains the Exponential Modified Shepard Method (EMSM) weighting values to use for each band.
MULTICHANNEL_EMSM table is used for the EMSM weighting and contains the wavelengths and associated region of interest size to use when IFU cubes are created from several bands and the final output is to have an IFU cube of varying spectral scale.
MULTICHANNEL_DRIZ table is used for the DRIZZLE weighting and contains the wavelengths to use when IFU cubes are created from several bands and the final output is to have an IFU cube of varying spectral scale.
The NIRSPEC reference table descriptions:
CUBEPAR table contains the spatial and spectral cube sample size for each band.
CUBEPAR_MSM table contains the Modified Shepard Method (MSM) weighting values to use for each band.
MULTICHAN_PRISM_MSM table is used for the MSM weighting and contains the wavelengths and associated region of interest size to use when IFU cubes are created from the grating prism and the final IFU Cube output has a varying spectral scale.
MULTICHAN_MED_MSM table is used for the MSM weighting and contains the wavelengths and associated region of interest size to use when IFU cubes are created from the medium resolution grating and the final IFU Cube output has a varying spectral scale.
MULTICHAN_HIGH_MSM table is used for the MSM weighting and contains the wavelengths and associated region of interest size to use when IFU cubes are created from the high resolution gratings and the final IFU Cube output has a varying spectral scale.
CUBEPAR_EMSM table contains the Exponential Modified Shepard Method (EMSM) weighting values to use for each band.
MULTICHAN_PRISM_EMSM table is used for the EMSM weighting and contains the wavelengths and associated region of interest size to use when IFU cubes are created from the grating prism and the final IFU Cube output has a varying spectral scale.
MULTICHAN_MED_EMSM table is used for the EMSM weighting and contains the wavelengths and associated region of interest size to use when IFU cubes are created from the medium resolution grating and the final IFU Cube output has a varying spectral scale.
MULTICHAN_HIGH_EMSM table is used for the EMSM weighting and contains the wavelengths and associated region of interest size to use when IFU cubes are created from the high resolution gratings and the final IFU Cube output has a varying spectral scale.