Scanamorphos *  for ArTéMiS


     version 3.2 available (September 2018)
     initial public delivery: v3 (March 2018)


    This incarnation of Scanamorphos is tailored to observations with the ArTéMiS camera installed at APEX ,
    operating at 350 and 450 µm.

    Please have a look at the documentation associated with the software initially developed for Herschel
    (at this location) to understand the data processing principles and steps.

     The user guide, also describing the algorithm modifications for ArTéMiS, is available here .

                                                                                                        ~o~

     Version 4 will soon be available. It is a major extension of the code, designed to produce hybrid maps
     combining the extended emission from SPIRE and the compact emission from ArTéMiS, taking advantage
     of both the exquisite sensitivity of SPIRE for diffuse emission and the much better resolving power of ArTéMiS.
     Here is a preview (all maps in square root scale) of three of the fields from the ESO Large Program CAFFEINE,
     reduced with this new version (Mattern et al., in preparation):

SPIRE 350 µm map (larger field)
 hybrid map at 350 µm
 hybrid map at 450 µm












  documentation and reference 
  download and installation 
  inquiries 
  acknowledgements 




Scanamorphos is an IDL software developed to build maps from scan observations made with bolometer arrays or other instruments subject to low-frequency noise, in particular with the PACS and SPIRE photometers onboard the Herschel space telescope (wavelength range of operation: 70 to 500 µm). It has now been adapted to other far-infrared and millimeter instruments, ground-based or balloon-borne.

Here are the main functionalities for ArTéMiS:
  • subtraction of linear baselines (brightness drifts with timescales larger than the scan leg duration)
  • subtraction of the average brightness drift (i.e. atmosphere + correlated instrumental drift), on timescales smaller than the scan leg duration
  • subtraction of the individual brightness drift of each bolometer (i.e. flicker noise), also on timescales smaller than the scan leg duration
  • detection and masking of glitches
  • projection of signal, error, drifts and weight maps on a spatial grid specified by the user, assuming axisymmetric bolometers.
The processing is fully automated, but ample visualization of intermediate results at various steps is enabled.
You will need the ArTéMiS pipeline for the calibration and opacity correction, and to reinject the processed data into the original data structures for further use. The  scanam_artemis  tree is available already grafted onto the pipeline, with its interface.



* portmanteau word composed of "scan" and "anamorphosis"
   anamorphosis: reversible transformation of an image by a mathematical or optical operator
   (from the Greek , implying the idea of a transposition or return; and : shape)
~o~


documentation and reference:

Please cite the companion paper when using Scanamorphos:

     Roussel, H.  2013, PASP 125, 1126

It contains a detailed description of the algorithm for Herschel, illustrations of the various processing steps drawn from SDP (Science Demonstration Phase) data, and the results of two PACS simulations.


The user guide for ArTéMiS is available on  arXiv:1803.04264  and should also be cited.
It is also provided here as a pdf file:   scanam_artemis_manual.pdf


Tutorials were given at the ESO Single Dish 2018 workshop to demonstrate how to calibrate and process ArTéMiS datasets. Here are the slides for the Scanamorphos part:   https://zenodo.org/record/1204984


~~o~~


download and installation:


 Scanamorphos is distributed under the terms of the GNU General Public License. You will need recent versions of IDL and the IDL Astronomy library.

You will also need to install the ArTéMiS pipeline, in charge of the initial formatting, calibration and opacity correction, and optionally the final projection.  Scanamorphos routines are separately available here for convenience (to allow decoupled releases).

Unpack the software archive below in the pipeline subdirectory named  apexpro/ . This will create or update a subdirectory named SCANAM_ARTEMIS/ .

    SCANAM_ARTEMIS_v3.2.tar

Then add the following routine in the same subdirectory  apexpro/ :
    get_calib_project_info.pro    (courtesy Frédéric Schuller)

For the processing, follow the instructions contained in the user guide.


~~~o~~~


inquiries, bug reports, suggestions for improvements or new functionalities:


 If you have questions or comments about any aspect of Scanamorphos, please contact me by electronic mail (roussel at iap dot fr). If you wish to be notified of updates, simply include "register scanam_artemis" in the subject field.

Scanamorphos is distributed to the astronomical community in the hope that it will be useful. But since the software could not be tested in any possible configuration, you may encounter bugs now and then. In this event, please give me a precise account (with the inputs and full error message), so that they can be fixed in patches and future releases.


~~~~o~~~~


acknowledgements:


 This work benefited from working within the Herschel, NIKA2, PILOT and ArTéMiS teams, whose members are collectively thanked.










Hélène Roussel
Institut d'Astrophysique de Paris
January 2024