Documentation

Last updated 28-jan-2026.

Program Documentation

A general description of GILDAS can be found in the quick introduction to GILDAS (pdf). GILDAS is composed of:

A kernel:
- SIC a command line interpreter with mathematical possibilities and direct access to internal and FITS data formats; SIC also includes a built-in GUI (Graphical User Interface) constructor; (pdf)
- GREG an all-purpose 1-D, 2-D and almost 3-D graphical program. GREG has many facilities for astronomical data manipulation and analysis; (pdf)
- GILDAS-Python a Gildas-Python binding is provided to the users who want to benefit the functionalities of both Gildas programs and Python in a single program session (pdf)
Interactive programs:
- General purpose:
  - ASTRO dedicated to ephemeris and observation preparation (e.g. NOEMA correlator setup); (pdf)
  - TELCAL a library dedicated to the calibration of the telescope (pointing, focus, gain, ...); (pdf)
- Single-dish data processing:
  - MRTCAL Current software dedicated to the calibration of the raw format (IMBFITS) and the writing in the CLASS data format of 30m spectra: user and programmer manuals;
  - MIRA Former software dedicated to the calibration of the raw format (IMBFITS) and the writing in the CLASS data format of 30m spectra obtained from 2006 to 2016 (pdf); the software to calibrate 30m spectra before that date (OTFCAL) is not supported anymore; related documentation can be found in the history section;
  - CLASS dedicated to the processing of single--dish spectra; CLASS (pdf) is oriented towards the processing of a large quantity of spectra (see IRAM memo 2005-1); WEEDS (pdf) is an extension of CLASS based on the GILDAS-Python binding; it accesses online spectral catalogs to ease the analysis of spectral surveys or spectral lines observations with large bandwidths; demonstration data and scripts are available.
  - PIIC The Pointing and Imaging In Continuum software (pdf, contact: piic@iram.fr) is developed by S. Berta at IRAM. It is the extension of the MOPSIC data reduction software (for MAMBO) to the case of NIKA2 data. For the moment, it is only distributed as generic Linux x86_64 binaries.
- Interferometer data processing:
  - CLIC dedicated to on-line and off-line calibration of NOEMA; (pdf)
  - MAPPING dedicated to imaging and deconvolution of aperture synthesis data (pdf)
Standalone tasks: Dedicated small programs to perform non interactive, time consuming processing such as transposition, fitting, reprojection, image processing, simulation, etc...

The programming manual gives all information required to develop new applications in GILDAS. It describes i) how to use the SIC command line monitor and the GREG graphical library, and ii) how to implement new GILDAS tasks.

NOEMA additional information

Proposal preparation
- An Introduction to the IRAM NOEMA interferometer is a description of the IRAM NOrthen Extented Milliter Array. This is a must for the astronomers preparing observing proposals.
- The Correlator Manual describes the possibilities of the correlator.
- Frequency Setup contains an accurate description of the frequency plan of the IRAM interferometer. This is useful when double sideband observations of narrow lines have to be planned.
Array operation
- Amplitude Calibration describes the primary amplitude calibration: atmospheric calibration receiver and telescope dependent parameters. This document also applies for the 30-m calibration.
- Interferometer Observer's Manual a complete observing manual for the interferometer.
- Flux measurements details the observing techniques for flux density measurements.
- Pointing User's Guide details the methods for pointing measurements and describes the POINT program.
- Trouble Shooting Guide contains a (non-exhaustive) list of potential problems, with their causes and a description of diagnostic tools.
Data calibration
- Calibration CookBook, a supplement to the CLIC manual, contains simple recipes to calibrate interferometer data.

History

Programs

OTFCAL dedicated to calibration of 30m On-The-Fly data obtained before 2006; for later data, users should use MIRA or MRTCAL; (pdf)

ALMA simulator

The ALMA simulator has been created to evaluate the importance of the ALMA Compact Array (ACA) on the wide field imaging performances of ALMA. All information about the simulator may be found in the following ALMA memos:

# 488: Wide use of the simulator by our japonese colleagues to help designing ACA;
# 398: The most up-to-date description of the simulator and final results;
# 387: Preliminary results;
# 386: First state of the simulator.