# calwebb_coron3: Stage 3 Coronagraphic Processing¶

Config

calwebb_coron3.cfg

Class

Coron3Pipeline

The stage 3 coronagraphic pipeline is to be applied to associations of calibrated NIRCam coronagraphic and MIRI Lyot and 4QPM exposures, and is used to produce PSF-subtracted, resampled, combined images of the source object.

The steps applied by the calwebb_coron3 pipeline are shown in the table below.

calwebb_coron3

outlier_detection

stack_refs

align_refs

klip

resample

The high-level processing provided by these steps is:

1. CR-flag all PSF and science target exposures

2. Accumulate all reference PSF images into a single product

3. Align every PSF image to every science target image

4. Compute an optimal PSF fit and subtract it from every science target image

5. Combine the PSF-subtracted and CR-flagged images into a single resampled image

Currently the individual steps shown above can only be run in a convenient way by running the calwebb_coron3 pipeline on an association (ASN) file that lists the various science target and reference PSF exposures to be processed.

## Arguments¶

The calwebb_coron3 pipeline does not have any optional arguments.

## Inputs¶

### 3D calibrated images¶

Data model

CubeModel

File suffix

_calints

The input to calwebb_coron3 must be in the form of an ASN file that lists one or more exposures of a science target and one or more reference PSF targets. The individual target and reference PSF exposures should be in the form of 3D calibrated (“_calints”) products from calwebb_image2 processing. Each pipeline step will loop over the 3D stack of per-integration images contained in each exposure.

An example ASN file containing 2 science target and 1 reference PSF target exposures is shown below. Only 1 product is defined, corresponding to the science target, with members consisting of exposures of both the science target and the reference PSF target, as indicated by the “exptype” values for each:

{"asn_type": "coron3",
"asn_rule": "candidate_Asn_Coron",
"program": "10005",
"asn_id": "c1001",
"target": "t001",
"asn_pool": "jw10005_20181020T033546_pool",
"products": [
"members": [
{"expname": "jw10005009001_02102_00001_nrcalong_calints.fits",
"exptype": "psf"
},
{"expname": "jw10005006001_02102_00001_nrcalong_calints.fits",
"exptype": "science"
},
{"expname": "jw10005003001_02102_00001_nrcalong_calints.fits",
"exptype": "science"
}
]
}
]
}


## Outputs¶

### CR-flagged images¶

Data model

CubeModel

File suffix

_crfints

If the outlier_detection step is applied, a new version of each exposure is created, in which the DQ array is updated to flag pixels detected as outliers. These files use the “_crfints” (CR-Flagged per integration) product type suffix and include the association candidate ID, e.g. “jw8607342001_02102_00001_nrcb3_a3001_crfints.fits.”

### 3D stacked PSF images¶

Data model

CubeModel

File suffix

_psfstack

The data from each input PSF reference exposure are concatenated into a single combined 3D stack by the stack_refs step, for use by subsequent steps. The stacked PSF data get written to disk in the form of a “_psfstack” product. The output file name is source-based, using the product name specified in the ASN file, e.g. “jw86073-a3001_t001_nircam_f140m-maskbar_psfstack.fits.”

### 4D aligned PSF images¶

Data model

QuadModel

File suffix

_psfalign

For each science target exposure, all of the reference PSF images in the “_psfstack” product are aligned to each science target integration and saved to a 4D “_psfalign” product by the align_refs step. The output file name is exposure-based, with the addition of the associated candidate ID, e.g. “jw8607342001_02102_00001_nrcb3_a3001_psfalign.fits.”

### 3D PSF-subtracted images¶

Data model

CubeModel

File suffix

_psfsub

For each science target exposure, the klip step applies PSF fitting and subtraction for each integration, resulting in a 3D stack of PSF-subtracted images. The data for each science target exposure are saved to a “_psfsub” product, using exposure-based file names, e.g. “jw8607342001_02102_00001_nrcb3_a3001_psfsub.fits.”

### 2D resampled image¶

Data model

DrizProductModel

File suffix

_i2d

The resample step is applied to the CR-flagged products to create a single resampled and combined product for the science target. The file name is source-based, using the product name specified in the ASN file, e.g. “jw86073-a3001_t001_nircam_f140m-maskbar_i2d.fits.”