Skip to content

Latest commit

 

History

History
80 lines (61 loc) · 2.87 KB

description.rst

File metadata and controls

80 lines (61 loc) · 2.87 KB
Raw

Description

Class

jwst.ami.AmiAnalyzeStep

Alias

ami_analyze

The ami_analyze step is one of the AMI-specific steps in the ami sub-package that is part of Stage 3 calwebb_ami3 <calwebb_ami3> processing. It applies the Lacour-Greenbaum (LG) image plane modeling algorithm to a NIRISS AMI image. The routine computes a number of parameters, including a model fit (and residuals) to the image, fringe amplitudes and phases, and closure phases and amplitudes.

The JWST AMI observing template allows for exposures to be obtained using either full-frame (SUBARRAY="FULL") or subarray (SUBARRAY="SUB80") readouts. When processing a full-frame exposure, the ami_analyze step extracts and processes a region from the image corresponding to the size and location of the SUB80 subarray, in order to reduce execution time.

Arguments

The ami_analyze step has four optional arguments:

--oversample

The oversampling factor to be used in the model fit (default=3).

--rotation

Initial guess for the rotation of the PSF in the input image, in units of degrees (default=0.0).

--psf_offset

List of PSF offset values to use when creating the model array (default='0.0 0.0').

--rotation_search

List of start, stop, and step values that define the list of rotation search values. The default setting of '-3 3 1' results in search values of [-3, -2, -1, 0, 1, 2, 3].

Inputs

2D calibrated image

Data model

~jwst.datamodels.ImageModel

File suffix

_cal

The ami_analyze step takes a single calibrated image as input, which should be the "_cal" product resulting from calwebb_image2 <calwebb_image2> processing. Multiple exposures can be processed via use of an ASN file that is used as input to the calwebb_ami3 <calwebb_ami3> pipeline. The ami_analyze step itself does not accept an ASN as input.

Outputs

LG model parameters

Data model

~jwst.datamodels.AmiLgModel

File suffix

_ami

The ami_analyze step produces a single output file, containing the following list of extensions:

  1. FIT: a 2D image of the fitted model
  2. RESID: a 2D image of the fit residuals
  3. CLOSURE_AMP: table of closure amplitudes
  4. CLOSURE_PHA: table of closure phases
  5. FRINGE_AMP: table of fringe amplitudes
  6. FRINGE_PHA: table of fringe phases
  7. PUPIL_PHA: table of pupil phases
  8. SOLNS: table of fringe coefficients

The output file name syntax is exposure-based, using the input file name as the root, with the addition of the association candidate ID and the "_ami" product type suffix, e.g. "jw87600027001_02101_00002_nis_a3001_ami.fits."

Reference Files

The ami_analyze step uses a THROUGHPUT reference file.