Reference Files¶
The straylight
step uses the MRSXARTCORR reference
file, which stores vectors describing the appropriate cross-artifact convolution kernel
for each MRS band. In Channel 1 these vectors include power in a broad Lorentzian core
plus a pair of double-Gaussian profiles. In Channels 2 and 3 these vectors include only
power in the broad Lorentzian, while in Channel 4 there is no correction.
MRSXARTCORR reference file¶
- REFTYPE
MRSXARTCORR
- Data models
The MRSXARTCORR reference file contains parameter values used to model and subtract the cross-artifact in the straylight step.
Reference Selection Keywords for MRSXARTCORR¶
CRDS selects appropriate MRSXARTCORR references based on the following keywords. MRSXARTCORR is not applicable for instruments not in the table.
Instrument |
Keywords |
---|---|
MIRI |
INSTRUME, EXP_TYPE, 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 MRSXARTCORR¶
In addition to the standard reference file keywords listed above, the following keywords are required in MRSXARTCORR reference files, because they are used as CRDS selectors (see Reference Selection Keywords for MRSXARTCORR):
Keyword |
Data Model Name |
---|---|
EXP_TYPE |
model.meta.exposure.type |
MIRI Reference File Format¶
The MIRI MRSXARTCORR reference files are FITS format, with 12 BINTABLE extensions. The FITS primary data array is assumed to be empty. The format and content of the MIRI MRSXARTCORR reference file
EXTNAME |
XTENSION |
Dimensions |
---|---|---|
1A |
BINTABLE |
TFIELDS = 7 |
1B |
BINTABLE |
TFIELDS = 7 |
1C |
BINTABLE |
TFIELDS = 7 |
2A |
BINTABLE |
TFIELDS = 7 |
2B |
BINTABLE |
TFIELDS = 7 |
2C |
BINTABLE |
TFIELDS = 7 |
3A |
BINTABLE |
TFIELDS = 7 |
3B |
BINTABLE |
TFIELDS = 7 |
3C |
BINTABLE |
TFIELDS = 7 |
4A |
BINTABLE |
TFIELDS = 7 |
4B |
BINTABLE |
TFIELDS = 7 |
4C |
BINTABLE |
TFIELDS = 7 |
The formats of the individual table extensions are listed below.
Table |
Column |
Data type |
Units |
---|---|---|---|
CH1A |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH1B |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH1C |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH2A |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH2B |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH2C |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH3A |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH3B |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH3C |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH4A |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH4B |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
|
CH4C |
YROW |
shortint |
pixels |
LOR_FWHM |
float |
pixels |
|
LOR_SCALE |
float |
N/A |
|
GAU_FWHM |
float |
pixels |
|
GAU_XOFF |
float |
pixels |
|
GAU_SCALE1 |
float |
N/A |
|
GAU_SCALE2 |
float |
N/A |
These reference files contain tables for each wavelength band giving the appropriate kernel properties to use to model the cross-artifact for each band. These include Lorentzian plus Gaussian models.
The MIRI reference table contains parameters for each band in the corresponding EXTNAME extension.