Reference File Types¶
The source_catalog
step uses APCORR, ABVEGAOFFSET, and PARS-SOURCECATALOGSTEP reference
files.
APCORR Reference File¶
- REFTYPE
APCORR
The APCORR reference file contains data necessary for correcting extracted imaging and spectroscopic photometry to the equivalent of an infinite aperture. It is used within the source_catalog step for imaging and within the extract_1d step for spectroscopic data.
Reference Selection Keywords for APCORR¶
CRDS selects appropriate APCORR references based on the following keywords. APCORR is not applicable for instruments not in the table. All keywords used for file selection are required.
Instrument |
Keywords |
---|---|
FGS |
INSTRUME, EXP_TYPE, DATE-OBS, TIME-OBS |
MIRI |
INSTRUME, EXP_TYPE, DATE-OBS, TIME-OBS |
NIRCam |
INSTRUME, EXP_TYPE, DATE-OBS, TIME-OBS |
NIRISS |
INSTRUME, EXP_TYPE, DATE-OBS, TIME-OBS |
NIRSpec |
INSTRUME, EXP_TYPE, FILTER, GRATING, LAMP, 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 APCORR¶
In addition to the standard reference file keywords listed above, the following keywords are required in APCORR reference files, because they are used as CRDS selectors (see Reference Selection Keywords for APCORR):
Keyword |
Data Model Name |
Instruments |
---|---|---|
EXP_TYPE |
model.meta.exposure.type |
All |
NON-IFU APCORR Reference File Format¶
APCORR reference files for non-IFU data are in FITS format. The FITS APCORR reference file contains tabular data in a BINTABLE extension with EXTNAME = ‘APCORR’. The FITS primary HDU does not contain a data array. The contents of the table extension varies for different instrument modes, as shown in the tables below.
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
FGS |
Image |
eefraction |
float |
scalar |
unitless |
radius |
float |
scalar |
pixels |
||
apcorr |
float |
scalar |
unitless |
||
skyin |
float |
scalar |
pixels |
||
skyout |
float |
scalar |
pixels |
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
MIRI |
Image |
filter |
string |
12 |
N/A |
subarray |
string |
15 |
N/A |
||
eefraction |
float |
scalar |
unitless |
||
radius |
float |
scalar |
pixels |
||
apcorr |
float |
scalar |
unitless |
||
skyin |
float |
scalar |
pixels |
||
skyout |
float |
scalar |
pixels |
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
MIRI |
LRS |
subarray |
string |
15 |
N/A |
wavelength |
float |
1D array |
micron |
||
nelem_wl |
integer |
scalar |
N/A |
||
size |
integer |
1D array |
pixels |
||
nelem_size |
integer |
scalar |
N/A |
||
apcorr |
float |
2D array |
unitless |
||
apcorr_err |
float |
2D array |
unitless |
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
NIRCam |
Image |
filter |
string |
12 |
N/A |
pupil |
string |
15 |
N/A |
||
eefraction |
float |
scalar |
unitless |
||
radius |
float |
scalar |
pixels |
||
apcorr |
float |
scalar |
unitless |
||
skyin |
float |
scalar |
pixels |
||
skyout |
float |
scalar |
pixels |
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
NIRCam |
WFSS |
filter |
string |
12 |
N/A |
pupil |
string |
15 |
N/A |
||
wavelength |
float |
1D array |
micron |
||
nelem_wl |
integer |
scalar |
N/A |
||
size |
integer |
1D array |
pixels |
||
nelem_size |
integer |
scalar |
N/A |
||
apcorr |
float |
2D array |
unitless |
||
apcorr_err |
float |
2D array |
unitless |
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
NIRISS |
Image |
filter |
string |
12 |
N/A |
pupil |
string |
15 |
N/A |
||
eefraction |
float |
scalar |
unitless |
||
radius |
float |
scalar |
pixels |
||
apcorr |
float |
scalar |
unitless |
||
skyin |
float |
scalar |
pixels |
||
skyout |
float |
scalar |
pixels |
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
NIRISS |
WFSS |
filter |
string |
12 |
N/A |
pupil |
string |
15 |
N/A |
||
wavelength |
float |
1D array |
micron |
||
nelem_wl |
integer |
scalar |
N/A |
||
size |
integer |
1D array |
pixels |
||
nelem_size |
integer |
scalar |
N/A |
||
apcorr |
float |
2D array |
unitless |
||
apcorr_err |
float |
2D array |
unitless |
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
NIRSpec |
FS |
filter |
string |
12 |
N/A |
grating |
string |
15 |
N/A |
||
slit |
string |
15 |
N/A |
||
wavelength |
float |
1D array |
micron |
||
nelem_wl |
integer |
scalar |
N/A |
||
size |
integer |
2D array |
arcsec |
||
nelem_size |
integer |
scalar |
N/A |
||
pixphase |
float |
1D array |
N/A |
||
apcorr |
float |
3D array |
unitless |
||
apcorr_err |
float |
3D array |
unitless |
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
NIRSpec |
MOS |
filter |
string |
12 |
N/A |
grating |
string |
15 |
N/A |
||
wavelength |
float |
1D array |
micron |
||
nelem_wl |
integer |
scalar |
N/A |
||
size |
integer |
2D array |
arcsec |
||
nelem_size |
integer |
scalar |
N/A |
||
pixphase |
float |
1D array |
N/A |
||
apcorr |
float |
3D array |
unitless |
||
apcorr_err |
float |
3D array |
unitless |
Row Selection¶
A row of data within the reference table is selected by the pipeline step based on the optical elements in use for the exposure. The selection attributes are always contained in the first few columns of the table. The remaining columns contain the data needed for the aperture correction. The row selection criteria for each instrument+mode are:
- FGS Image:
None (table contains a single row)
- MIRI:
Image: Filter and Subarray
LRS: Subarray
- NIRCam:
Image: Filter and Pupil
WFSS: Filter and Pupil
- NIRISS:
Image: Filter and Pupil
WFSS: Filter and Pupil
- NIRSpec:
MOS: Filter and Grating
Fixed Slits: Filter, Grating, and Slit name
Note: Spectroscopic mode reference files contain the “nelem_wl” and “nelem_size” entries, which indicate to the pipeline step how many valid elements are contained in the “wavelength” and “size” arrays, respectively. Only the first “nelem_wl” and “nelem_size” entries are read from each array.
IFU APCORR Reference File ASDF Format¶
For IFU data the APCORR reference files are in ASDF format. The aperture correction varies with wavelength and the contents of the files are shown below. The radius, aperture correction and error are all 2D arrays. Currently the 2nd dimension does not add information, but in the future it could be used to provide different aperture corrections for different radii.
- Data model
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
MIRI |
MRS |
wavelength |
float |
1D array |
micron |
radius |
float |
2D array |
arcsec |
||
apcorr |
float |
2D array |
unitless |
||
apcorr_err |
float |
2D array |
unitless |
- Data model
NRSIFUApcorrModel
Instrument |
Mode |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|---|
NIRSpec |
MOS |
filter |
string |
12 |
N/A |
grating |
string |
15 |
N/A |
||
wavelength |
float |
1D array |
micron |
||
radius |
float |
2D array |
arcsec |
||
apcorr |
float |
2D array |
unitless |
||
apcorr_err |
float |
2D array |
unitless |
ABVEGAOFFSET Reference File¶
- REFTYPE
ABVEGAOFFSET
- Data model
The ABVEGAOFFSET reference file contains data necessary for converting from AB to Vega magnitudes.
Reference Selection Keywords for ABVEGAOFFSET¶
CRDS selects appropriate ABVEGAOFFSET references based on the following keywords. ABVEGAOFFSET is not applicable for instruments not in the table. All keywords used for file selection are required.
Instrument |
Keywords |
---|---|
FGS |
INSTRUME, EXP_TYPE, DATE-OBS, TIME-OBS |
MIRI |
INSTRUME, EXP_TYPE, DATE-OBS, TIME-OBS |
NIRCam |
INSTRUME, EXP_TYPE, DATE-OBS, TIME-OBS |
NIRISS |
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
ABVEGAOFFSET Reference File Format¶
ABVEGAOFFSET reference files are in ASDF format. The ABVEGAOFFSET
reference file contains tabular data in a key called
abvega_offset
. The content of the table varies for different
instrument modes, as shown in the tables below.
Instrument |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|
FGS |
detector |
string |
7 |
N/A |
abvega_offset |
float |
scalar |
unitless |
Instrument |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|
MIRI |
filter |
string |
12 |
N/A |
abvega_offset |
float |
scalar |
unitless |
Instrument |
Column name |
Data type |
Dimensions |
Units |
---|---|---|---|---|
NIRCam or NIRISS |
filter |
string |
12 |
N/A |
pupil |
string |
15 |
N/A |
|
abvega_offset |
float |
scalar |
unitless |
Row Selection¶
A row of data within the reference table is selected by the pipeline step based on the optical elements in use for the exposure. The selection attributes are always contained in the first few columns of the table. The last column contains the data needed to convert from AB to Vega magnitudes. The row selection criteria for each instrument/mode are:
- FGS:
Detector
- MIRI:
Filter
- NIRCam:
Filter and Pupil
- NIRISS:
Filter and Pupil
PARS-SOURCECATALOGSTEP Parameter Reference File¶
- REFTYPE
PARS-SOURCECATALOGSTEP
- Data model
N/A
Reference Selection Keywords¶
CRDS selects appropriate pars-sourcecatalogstep references based on the following keywords.
Instrument |
Keywords |
---|---|
FGS |
EXP_TYPE |
MIRI |
EXP_TYPE, FILTER |
NIRCAM |
EXP_TYPE, FILTER |
NIRISS |
EXP_TYPE, FILTER |
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