Reference Files

The spectral_leak step uses the MRSPTCORR reference file.

MRSPTCORR reference file

REFTYPE:

MRSPTCORR

Data models:

MirMrsPtCorrModel

The MRSPTCORR reference file contains parameter values used to subtract the MRS 12 micron spectral leak in the spectral leak step. It also contains parameters to correct point sources, in future enhancements, for across-slice corrections and throughput variations.

Reference Selection Keywords for MRSPTCORR

CRDS selects appropriate MRSPTCORR references based on the following keywords. MRSPTCORR 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 MRSPTCORR

In addition to the standard reference file keywords listed above, the following keywords are required in MRSPTCORR reference files, because they are used as CRDS selectors (see Reference Selection Keywords for MRSPTCORR):

Keyword	Data Model Name
EXP_TYPE	model.meta.exposure.type

MIRI Reference File Format

The MIRI MRSPTCORR 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 MRSPTCORR reference file

EXTNAME	XTENSION	Dimensions
LEAKCOR	BINTABLE	TFIELDS = 3
TRACOR	BINTABLE	TFIELDS = 7
WAVCORR_OPTICAL	BINTABLE	TFIELDS = 6
WAVCORR_XSLICE	BINTABLE	TFIELDS = 2
WAVCORR_SHIFT	BINTABLE	TFIELDS = 3

The formats of the individual table extensions are listed below.

Table	Column	Data type	Units
LEAKCOR	WAVELENGTH	float	micron
	FRAC_LEAK	float	N/A
	ERR_LEAK	float	N/A
TRACOR	CHANNEL	int	N/A
	WAVE_MIN	float	micron
	WAVE_MAX	float	micron
	T_WMIN_CENTRE	float	percent
	T_WMIN_EDGE	float	percent
	T_WMAX_CENTRE	float	percent
	T_WMAX_EDGE	float	percent
WAVCORR_OPTICAL	SUB_BAND	string	N/A
	BETA_SLICE	float	arcsec
	WAVE_MIN	float	micron
	WAVE_MAX	float	micron
	SRP_MIN	float	N/A
	SRP_MAX	float	N/A
WAVCORR_XSLICE	XSLICE_MIN	float	micron/arcsec
	XSLICE_MAX	float	micron/arcsec
WAVCORR_SHIFT	BETA_OFF	float	slice
	DS_MIN	float	slice
	DS_MAX	float	slice

This reference file contains the relative spectrophotometric response function for the MRS 12 micron spectral leak, along with tables of across-slice wavelength and throughput variations for point sources in each of the MRS bands. Currently, only the LEAKCOR table is use in the jwst pipeline.