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AMICAL Documentation

Aperture Masking Interferometry Calibration and Analysis Library

What can AMICAL do for you ?

AMICAL is developed to provide an easy-to-use solution to process Aperture Masking Interferometry (AMI) data from major existing facilities: NIRISS on the JWST (first scientific interferometer operating in space), SPHERE and VISIR from the European Very Large Telescope (VLT) and VAMPIRES from SUBARU telescope (and more to come).

We focused our efforts to propose a user-friendly interface, though different sub-classes allowing to (1) Clean the reduced datacube from the standard instrument pipelines, (2) Extract the interferometrical quantities (visibilities and closure phases) using a Fourier sampling approach and (3) Calibrate those quantities to remove the instrumental biases.

AMICAL's job ends at (4) the calibrated OIFITS file. To analyse it (binary searches, contrast limits, model fitting and posteriors), we recommend virgil (pip install amical[virgil]), which reads AMICAL's OIFITS files directly. AMICAL no longer bundles CANDID and Pymask: amical.candid_grid, amical.pymask_mcmc and the other functions that used them remain as a legacy API, computed with virgil, and amical.smartfit is deprecated. See the companion search tutorial for both.

Getting started

Looking for a quickstart into AMICAL? You can go through our getting started tutorial explaining how to use its different features.

You can also have a look to the tutorials for NIRISS and SPHERE or see how to analyse the calibrated OIFITS file in the companion search tutorial.

Use policy and reference publication

If you use AMICAL in a publication, we encourage you to properly cite the reference paper published during the 2020 SPIE conference:

The James Webb Space Telescope aperture masking interferometer

with BibTex:

@INPROCEEDINGS{2020SPIE11446E..11S,
       author = {{Soulain}, A. and {Sivaramakrishnan}, A. and {Tuthill}, P. and {Thatte}, D. and {Volk}, K. and {Cooper}, R. and {Albert}, L. and {Artigau}, {\'E}. and {Cook}, N. and {Doyon}, R. and {Johnstone}, D. and {Lafreni{\`e}re}, D. and {Martel}, A.},
        title = "{The James Webb Space Telescope aperture masking interferometer}",
     keywords = {Astrophysics - Instrumentation and Methods for Astrophysics},
    booktitle = {Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series},
         year = 2020,
       series = {Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series},
       volume = {11446},
        month = dec,
          eid = {1144611},
        pages = {1144611},
          doi = {10.1117/12.2560804},
archivePrefix = {arXiv},
       eprint = {2201.01524},
 primaryClass = {astro-ph.IM},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2020SPIE11446E..11S},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

Acknowledgements

This work is mainly a modern Python translation of the very well known (and old) IDL pipeline used to process and analyze Sparse Aperture Masking data. This pipeline, called "Sydney code", was developed by a lot of people over many years. Credit goes to the major developers, including Peter Tuthill, Mike Ireland and John Monnier. Many forks exist across the web and the last IDL version can be found here.

Contributors

New contributions are always welcome! If you wish to contribute to AMICAL, take a look at CONTRIBUTING.md.

AMICAL core developers:

IDL Masking Code:

The analysis functions were originally interfaces to the following packages (now replaced by virgil):

Pymask:

CANDID: